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this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
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We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
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The UniProt accession Q88E13 corresponds to pcaG/PP_4655 in Pseudomonas putida KT2440 and encodes the α-subunit of protocatechuate 3,4-dioxygenase (PcaGH; EC 1.13.11.3), the canonical intradiol ring-cleaving dioxygenase of the protocatechuate (PCA) branch of the β-ketoadipate pathway. This mapping is explicitly used in KT2440 metabolic-engineering work referring to pcaGH (PP_4655–PP_4656) as the protocatechuate 3,4-dioxygenase step. (jin2024biologicalvalorizationof pages 1-2, valderramagomez2020mechanisticmodelingof pages 33-36)
Protocatechuate 3,4-dioxygenase (PcaGH) catalyzes intradiol (ortho) cleavage of the aromatic ring of protocatechuate (3,4-dihydroxybenzoate; PCA), producing 3-carboxy-cis,cis-muconate (also termed β-carboxy-cis,cis-muconate), a central intermediate that is further metabolized toward TCA-cycle entry in the β-ketoadipate pathway. (chow2024confirmationofgenesa pages 11-15, valderramagomez2020mechanisticmodelingof pages 33-36)
A systems-level description of this enzymatic step is:
- PCA ⇌ β-carboxy-cis,cis-muconate (PcaGH-catalyzed). (valderramagomez2020mechanisticmodelingof pages 33-36)
PcaG belongs to the intradiol ring-cleavage dioxygenase family (intradiol dioxygenases / IDOs). Mechanistic structural work on protocatechuate 3,4-dioxygenase-type intradiol enzymes established that the catalytic metal is Fe(III) coordinated by a 2-His/2-Tyr ligand set, and crystallography captured alkylperoxo and anhydride intermediates following O2 addition, supporting a detailed intradiol O2-activation mechanism. (knoot2015crystalstructuresof pages 1-3)
Although this mechanistic evidence is not specific to the KT2440 protein sequence, it represents the authoritative biochemical framework currently used to interpret PcaGH-class catalysis. (knoot2015crystalstructuresof pages 1-3)
The physiological substrate of PcaGH is protocatechuate; however, KT2440-focused work indicates PcaHG can also catalyze intradiol cleavage of gallate, and that such activity is relevant for engineered conversion of syringyl-derived intermediates (e.g., gallate, 3-methoxy-gallate-related metabolites) toward downstream products such as 2-pyrone-4,6-dicarboxylate (PDC) via rearrangement/cyclization chemistry of ring-cleavage products. (dumalo2020dioxygenasesinthe pages 39-44, dumalo2020dioxygenasesinthe pages 32-39)
A mechanistic modeling study of the protocatechuate pathway describes the relevant structural genes as being expressed from a polycistronic mRNA (pcaBKCHG) and highlights that protocatechuate uptake can involve PcaK, a transporter capable of importing PCA into the cell. (valderramagomez2020mechanisticmodelingof pages 33-36)
Regulation is mediated by PcaU, an IclR-family transcriptional regulator that functions as an activator in the presence of the inducer protocatechuate and as a repressor in its absence (i.e., a bidirectional regulator depending on ligand). This PCA-responsive regulation has been exploited for biosensor engineering in KT2440 (below). (valderramagomez2020mechanisticmodelingof pages 33-36, jha2018aprotocatechuatebiosensor pages 3-4)
All evidence in the retrieved KT2440 literature is consistent with PcaG functioning as an intracellular (cytosolic) enzyme in aromatic catabolism: ΔpcaGH blocks intracellular PCA catabolism and yields intracellular PCA accumulation phenotypes; additionally, PcaK is described as a PCA importer (implying intracellular metabolism). Direct microscopy-based localization experiments for KT2440 PcaG were not identified in the retrieved sources. (jha2018aprotocatechuatebiosensor pages 2-3, valderramagomez2020mechanisticmodelingof pages 33-36)
A 2024 metabolic-engineering study in P. putida KT2440 used pcaGH deletion to prevent ring cleavage of PCA and thereby accumulate protocatechuic acid from lignin-derived aromatic inputs (“biological funneling”). The work reports:
- From corncob hydrolysates: 253.88 mg/L PCA (70.85% yield) and a maximum 433.72 mg/L PCA without additional nutrients. (Jin et al., 2024-03, Molecules, https://doi.org/10.3390/molecules29071555) (jin2024biologicalvalorizationof pages 1-2)
- In a ΔpcaGH strain (KT1), near-complete conversion of 1 g/L model phenolics to PCA with yields 97.7% (p-coumarate), 98.5% (4-hydroxybenzaldehyde), and 93.1% (4-hydroxybenzoate) under the tested conditions. (jin2024biologicalvalorizationof pages 4-7)
The pathway-level rationale is visually summarized in the study’s pathway diagram, where pcaGH is the downstream ring-cleavage step whose removal diverts flux to PCA accumulation. (jin2024biologicalvalorizationof media 66b82404)
The same 2024 KT2440 engineering work also emphasizes that blocking PCA cleavage (ΔpcaGH) can be combined with modulation of upstream steps (e.g., vanillate O-demethylation and related conversions) to improve funneling from complex aromatic mixtures. The study reports that ΔpcaGH did not cause a discernible growth defect in glucose-supplemented conditions, suggesting that in some process designs cells can grow on alternative carbon sources while PCA accumulates as a product. (jin2024biologicalvalorizationof pages 7-9)
Within the retrieved corpus, the highest-resolution mechanistic evidence remains the crystallographic capture of catalytic intermediates in an intradiol ring-cleaving dioxygenase (PCD-type), including Fe(III) coordination and peroxo/anhydride intermediates. These data strongly inform how researchers interpret substrate scope, reaction intermediates, and potential engineering strategies (e.g., expanding substrate acceptance). (Knoot et al., 2015-12, PNAS, https://doi.org/10.1073/pnas.1419118112) (knoot2015crystalstructuresof pages 1-3)
The most direct real-world application evidenced here is bioproduction of PCA from lignin-derived aromatics using engineered KT2440 strains with ΔpcaGH as the key flux-blocking modification, demonstrating production directly from complex biomass hydrolysates with quantified titers and yields. (jin2024biologicalvalorizationof pages 1-2)
A table and fermentation profiles in the 2024 study summarize PCA production outcomes across substrates and hydrolysates, providing an at-a-glance quantitative benchmark for process design. (jin2024biologicalvalorizationof media dc814145, jin2024biologicalvalorizationof media 7fa8d197)
A protocatechuate biosensor was ported and evolved in P. putida KT2440 by leveraging the PCA-responsive regulator PcaU. In KT2440 backgrounds engineered for PCA accumulation (ΔpcaHG strain CJ072), the best evolved variant (T147G/D148Y in PcaU) detected exogenous PCA below 0.003 mM with >12-fold contrast ratio, enabling high-throughput screening and pathway debugging for lignin-valorization strain engineering. (Jha et al., 2018-06, Metabolic Engineering Communications, https://doi.org/10.1016/j.meteno.2018.03.001) (jha2018aprotocatechuatebiosensor pages 4-5)
KT2440 work on syringyl aromatic catabolism describes engineering strategies that include overexpression of pcaHG (e.g., chromosomal Ptac-driven pcaHG) and pathway blocking (e.g., ΔgalA) to increase production of 2-pyrone-4,6-dicarboxylate (PDC) from syringate-related inputs, consistent with PcaHG’s capacity to cleave gallate and generate intermediates that can cyclize to PDC. (dumalo2020dioxygenasesinthe pages 32-39, dumalo2020dioxygenasesinthe pages 39-44)
The retrieved literature converges on a clear interpretation: pcaGH is the commitment step that prevents PCA accumulation, because once PCA is cleaved to carboxymuconate, flux is directed into the central β-ketoadipate pathway rather than remaining as an aromatic acid product. Therefore, ΔpcaGH is a canonical chassis edit to:
- accumulate PCA as a product, or
- enable PCA-dependent biosensors to report intracellular PCA, or
- redirect flux from native mineralization toward value-added products.
This control-point logic is directly demonstrated by high-yield PCA accumulation upon ΔpcaGH in KT2440. (jin2024biologicalvalorizationof pages 4-7, jha2018aprotocatechuatebiosensor pages 4-5)
For functional annotation, coupling enzymatic function (PcaGH) with PcaU-mediated regulation and PcaK-mediated uptake provides a coherent picture of a modular catabolic unit: PCA enters the cell (PcaK), induces the local regulator (PcaU), and is then cleaved by PcaGH, which is the key “ring-opening” bottleneck connecting lignin-derived aromatics to central metabolism. (valderramagomez2020mechanisticmodelingof pages 33-36)
The following table consolidates key annotation facts, mechanism, regulation, localization, and application-relevant quantitative data.
| Aspect | Key points | Evidence/notes |
|---|---|---|
| Identity / verification | pcaG = PP_4655 = α-subunit of protocatechuate 3,4-dioxygenase (PcaGH) in Pseudomonas putida KT2440; enzyme is a heterodimeric/oligomeric intradiol dioxygenase with β-subunit pcaH. | KT2440 engineering papers explicitly refer to pcaGH (PP_4655-4656) as protocatechuate 3,4-dioxygenase; biosensor work identifies pcaH/pcaG as the two-subunit PCA 3,4-dioxygenase; modeling paper states α = pcaG, β = pcaH. (jin2024biologicalvalorizationof pages 1-2, jha2018aprotocatechuatebiosensor pages 2-3, valderramagomez2020mechanisticmodelingof pages 33-36) |
| Reaction | Catalyzes intradiol 3,4-cleavage of protocatechuate (PCA) to 3-carboxy-cis,cis-muconate (also written β-carboxy-cis,cis-muconate). This is the ring-opening step of the PCA branch. | Bacterial PCA pathway summary names the product as 3-carboxy-cis,cis-muconic acid; modeling paper assigns reversible conversion PCA ↔ β-carboxy-cis,cis-muconate. (chow2024confirmationofgenesa pages 11-15, valderramagomez2020mechanisticmodelingof pages 33-36) |
| Enzyme class / mechanism | Member of the intradiol ring-cleaving dioxygenase family; mechanism proceeds through O2 addition and peroxo/anhydride intermediates characteristic of Fe-dependent intradiol cleavage chemistry. | Structural/mechanistic studies on 3,4-PCD captured alkylperoxo and anhydride intermediates and define it as an intradiol dioxygenase. (knoot2015crystalstructuresof pages 1-3) |
| Cofactor / active site | Active site contains Fe3+ coordinated by a 2-His/2-Tyr ligand set; tyrosines contribute ligand-to-metal charge transfer features. | High-confidence mechanistic evidence from crystal structures of 3,4-PCD. (knoot2015crystalstructuresof pages 1-3) |
| Substrates / specificity | Primary physiological substrate is protocatechuate. In KT2440-focused biochemical work, PcaHG also cleaves gallate, with expected lower specificity than for protocatechuate; products were investigated as (Z)-OMAe and PDC in engineering contexts. | KT2440 thesis work specifically tested protocatechuate and gallate, hypothesizing lower specificity for gallate and linking activity to PDC production. (dumalo2020dioxygenasesinthe pages 39-44, dumalo2020dioxygenasesinthe pages 32-39) |
| Quantitative mechanistic data | For 3,4-PCD with alternative substrate 4-fluorocatechol: observable stopped-flow steps had RRTs 0.92, 0.50, and 0.16 s−1; apparent Kd ≈ 7.5 mM for the initial weak complex; overall substrate Kd predicted ≈ 88 μM, direct titration ≈ 75 μM. | These values come from a mechanistic 3,4-PCD study and are informative for enzyme behavior, though not KT2440-specific in vivo physiology. (knoot2015crystalstructuresof pages 1-3) |
| Pathway role | Central enzyme of the β-ketoadipate / protocatechuate branch, funnelling diverse aromatics after biological funneling to PCA toward central metabolism / TCA-cycle entry. | Reviews and KT2440 engineering papers place pcaGH at the PCA ring-cleavage step connecting lignin-derived aromatic catabolism to central carbon metabolism. (dumalo2020dioxygenasesinthe pages 32-39, jin2024biologicalvalorizationof pages 4-7, perez‐pantoja2012genomicanalysisof pages 10-12, jin2024biologicalvalorizationof media 66b82404) |
| Gene organization | pca catabolic genes in Pseudomonas are classically named pcaGH, pcaB, pcaC, pcaD; one systems model represents structural genes on a polycistronic pcaBKCHG mRNA. | Useful for functional annotation, though organization can vary across taxa and publications. (chow2024confirmationofgenesa pages 11-15, valderramagomez2020mechanisticmodelingof pages 33-36) |
| Regulation | PcaU is the local regulator: an IclR-family transcription factor that acts as activator in the presence of protocatechuate and repressor in its absence; PcaU-based regulatory parts were portable enough to engineer a PCA biosensor in KT2440. | Modeling and biosensor papers support PCA-responsive regulation through PcaU. (valderramagomez2020mechanisticmodelingof pages 33-36, jha2018aprotocatechuatebiosensor pages 3-4, jha2018aprotocatechuatebiosensor pages 1-2) |
| Transport context | PcaK can transport protocatechuate into the cell, coupling uptake to pca pathway function. | Relevant to interpreting intracellular PCA availability and pcaGH knockout phenotypes. (valderramagomez2020mechanisticmodelingof pages 33-36) |
| Cellular localization | Evidence supports an intracellular/cytosolic role in aromatic catabolism rather than secretion or membrane localization. | Biosensor/pathway studies describe intracellular PCA accumulation/catabolism; ring-cleavage enzymes in these studies are treated as intracellular pathway enzymes. Direct localization experiment for KT2440 PcaG was not identified in retrieved sources. (valderramagomez2020mechanisticmodelingof pages 33-36, jha2018aprotocatechuatebiosensor pages 2-3, jin2024biologicalvalorizationof pages 4-7) |
| KT2440 knockout phenotype | ΔpcaGH blocks PCA ring cleavage, allowing PCA accumulation and preventing further catabolism through the native β-ketoadipate pathway. In glucose-containing media, knockout reportedly had no discernible impact on growth in one study. | Seen in KT2440 strains used for PCA accumulation and sensor characterization. (jin2024biologicalvalorizationof pages 4-7, jin2024biologicalvalorizationof pages 7-9, jha2018aprotocatechuatebiosensor pages 3-4) |
| KT2440 engineering: PCA accumulation from model aromatics | In engineered KT2440 KT1 (ΔpcaGH), PCA yields from 1 g/L substrates were 97.7% from p-coumarate, 98.5% from 4-hydroxybenzaldehyde, and 93.1% from 4-hydroxybenzoate. | Demonstrates that blocking pcaGH efficiently diverts flux to PCA accumulation. (jin2024biologicalvalorizationof pages 4-7) |
| KT2440 engineering: vanAB overexpression with ΔpcaGH | In KT2, endogenous vanAB overexpression on top of ΔpcaGH increased PCA yield from 2.61% to 75.63% for ferulic acid; strain also converted 10 g/L p-coumarate to 6.11 g/L PCA in 72 h; with ferulate, 2.5 g/L consumed and 1.9 g/L PCA after 72 h. | Shows pcaGH deletion is a key chassis modification for lignin-monomer valorization. (jin2024biologicalvalorizationof pages 7-9) |
| KT2440 engineering: hydrolysate valorization | In 2024 hydrolysate work, engineered KT2440 produced 253.88 mg/L PCA at 70.85% yield from one corncob hydrolysate and 433.72 mg/L PCA from another without added nutrients. | Figure/pathway summary explicitly shows pcaGH knockout as the enabling design feature. (jin2024biologicalvalorizationof pages 1-2, jin2024biologicalvalorizationof media 66b82404) |
| KT2440 engineering: gallate/PDC route | Chromosomal overexpression of pcaHG (e.g., Ptac:pcaHG) in KT2440 was used to enhance conversion of syringate/gallate-derived intermediates toward 2-pyrone-4,6-dicarboxylate (PDC). | Highlights that pcaG can be used both as a knockout target (to accumulate PCA) and an overexpression target (to drive ring-cleavage chemistry on noncanonical substrates). (dumalo2020dioxygenasesinthe pages 32-39, dumalo2020dioxygenasesinthe pages 39-44) |
| Biosensor application | A PcaU-based PCA biosensor evolved in KT2440 detected PCA at <0.003 mM with >12-fold contrast ratio; FACS selections used inductions from 0.01–10 mM PCA and selected the top 1% induced cells after pre-clearing the bottom 40% dark population. | While not measuring PcaG directly, this is a practical KT2440 application exploiting native PCA/pca regulation and ΔpcaGH backgrounds. (jha2018aprotocatechuatebiosensor pages 4-5, jha2018aprotocatechuatebiosensor pages 2-3) |
| Interpretation for annotation | Best-supported annotation for Q88E13 / PP_4655: intracellular α-subunit of the Fe(III)-dependent protocatechuate 3,4-dioxygenase that catalyzes intradiol ring opening of PCA in the β-ketoadipate pathway; highly relevant to lignin-derived aromatic catabolism and metabolic engineering in KT2440. | Consolidated from organism-specific and mechanistic sources. (jin2024biologicalvalorizationof pages 1-2, jin2024biologicalvalorizationof pages 4-7, valderramagomez2020mechanisticmodelingof pages 33-36, knoot2015crystalstructuresof pages 1-3, jin2024biologicalvalorizationof media 66b82404) |
Table: This table summarizes the verified identity, biochemical function, pathway context, regulation, localization, and engineering relevance of Pseudomonas putida KT2440 pcaG (UniProt Q88E13/PP_4655). It also captures key numeric results from recent KT2440 metabolic-engineering studies and supporting mechanistic work.
References
(jin2024biologicalvalorizationof pages 1-2): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(valderramagomez2020mechanisticmodelingof pages 33-36): Miguel Á. Valderrama-Gómez, Jason G. Lomnitz, Rick A. Fasani, and Michael A. Savageau. Mechanistic modeling of biochemical systems without a priori parameter values using the design space toolbox v.3.0. iScience, 23:101200, Jun 2020. URL: https://doi.org/10.1016/j.isci.2020.101200, doi:10.1016/j.isci.2020.101200. This article has 15 citations and is from a peer-reviewed journal.
(chow2024confirmationofgenesa pages 11-15): N Chow. Confirmation of genes involved in the degradation of protocatechuate in aspergillus niger through characterization of their encoded enzymes. Unknown journal, 2024.
(knoot2015crystalstructuresof pages 1-3): Cory J. Knoot, Vincent M. Purpero, and John D. Lipscomb. Crystal structures of alkylperoxo and anhydride intermediates in an intradiol ring-cleaving dioxygenase. Proceedings of the National Academy of Sciences, 112:388-393, Dec 2015. URL: https://doi.org/10.1073/pnas.1419118112, doi:10.1073/pnas.1419118112. This article has 48 citations and is from a highest quality peer-reviewed journal.
(dumalo2020dioxygenasesinthe pages 39-44): Linda Dumalo. Dioxygenases in the catabolism of syringols in pseudomonas putida kt2440. ArXiv, Jan 2020. URL: https://doi.org/10.14288/1.0394310, doi:10.14288/1.0394310. This article has 0 citations.
(dumalo2020dioxygenasesinthe pages 32-39): Linda Dumalo. Dioxygenases in the catabolism of syringols in pseudomonas putida kt2440. ArXiv, Jan 2020. URL: https://doi.org/10.14288/1.0394310, doi:10.14288/1.0394310. This article has 0 citations.
(jha2018aprotocatechuatebiosensor pages 3-4): Ramesh K. Jha, Jeremy M. Bingen, Christopher W. Johnson, Theresa L. Kern, Payal Khanna, Daniel S. Trettel, Charlie E.M. Strauss, Gregg T. Beckham, and Taraka Dale. A protocatechuate biosensor for pseudomonas putida kt2440 via promoter and protein evolution. Jun 2018. URL: https://doi.org/10.1016/j.meteno.2018.03.001, doi:10.1016/j.meteno.2018.03.001. This article has 54 citations and is from a peer-reviewed journal.
(jha2018aprotocatechuatebiosensor pages 2-3): Ramesh K. Jha, Jeremy M. Bingen, Christopher W. Johnson, Theresa L. Kern, Payal Khanna, Daniel S. Trettel, Charlie E.M. Strauss, Gregg T. Beckham, and Taraka Dale. A protocatechuate biosensor for pseudomonas putida kt2440 via promoter and protein evolution. Jun 2018. URL: https://doi.org/10.1016/j.meteno.2018.03.001, doi:10.1016/j.meteno.2018.03.001. This article has 54 citations and is from a peer-reviewed journal.
(jin2024biologicalvalorizationof pages 4-7): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(jin2024biologicalvalorizationof media 66b82404): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(jin2024biologicalvalorizationof pages 7-9): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(jin2024biologicalvalorizationof media dc814145): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(jin2024biologicalvalorizationof media 7fa8d197): Xinzhu Jin, Xiaoxia Li, Lihua Zou, Zhaojuan Zheng, and Jia Ouyang. Biological valorization of lignin-derived aromatics in hydrolysate to protocatechuic acid by engineered pseudomonas putida kt2440. Molecules, 29:1555, Mar 2024. URL: https://doi.org/10.3390/molecules29071555, doi:10.3390/molecules29071555. This article has 15 citations.
(jha2018aprotocatechuatebiosensor pages 4-5): Ramesh K. Jha, Jeremy M. Bingen, Christopher W. Johnson, Theresa L. Kern, Payal Khanna, Daniel S. Trettel, Charlie E.M. Strauss, Gregg T. Beckham, and Taraka Dale. A protocatechuate biosensor for pseudomonas putida kt2440 via promoter and protein evolution. Jun 2018. URL: https://doi.org/10.1016/j.meteno.2018.03.001, doi:10.1016/j.meteno.2018.03.001. This article has 54 citations and is from a peer-reviewed journal.
(perez‐pantoja2012genomicanalysisof pages 10-12): Danilo Pérez‐Pantoja, Raúl Donoso, Loreine Agulló, Macarena Córdova, Michael Seeger, Dietmar H. Pieper, and Bernardo González. Genomic analysis of the potential for aromatic compounds biodegradation in burkholderiales. Environmental microbiology, 14 5:1091-117, May 2012. URL: https://doi.org/10.1111/j.1462-2920.2011.02613.x, doi:10.1111/j.1462-2920.2011.02613.x. This article has 416 citations and is from a domain leading peer-reviewed journal.
(jha2018aprotocatechuatebiosensor pages 1-2): Ramesh K. Jha, Jeremy M. Bingen, Christopher W. Johnson, Theresa L. Kern, Payal Khanna, Daniel S. Trettel, Charlie E.M. Strauss, Gregg T. Beckham, and Taraka Dale. A protocatechuate biosensor for pseudomonas putida kt2440 via promoter and protein evolution. Jun 2018. URL: https://doi.org/10.1016/j.meteno.2018.03.001, doi:10.1016/j.meteno.2018.03.001. This article has 54 citations and is from a peer-reviewed journal.