UniProtKB entry for Pseudomonas putida KT2440 PP_2928
OpenScientist PSEPK carboxyspermidine pathway review
An alternative polyamine biosynthetic pathway is widespread in bacteria and essential for biofilm formation in Vibrio cholerae.
-
The study experimentally identifies paired CANSDH/CANSDC enzymes in the alternative bacterial polyamine pathway.
"deletion of either CANSDC or the putative CANSDH led to loss of sym-norspermidine and spermidine"
Structural analysis of carboxyspermidine dehydrogenase from Helicobacter pylori.
-
The study defines NADPH-dependent condensation of putrescine and aspartate semialdehyde by CASDH.
"CASDH condenses putrescine and aspartate β-semialdehyde into carboxyspermidine in an NADPH-dependent manner."
Alternative spermidine biosynthetic route is critical for growth of Campylobacter jejuni and is the dominant polyamine pathway in human gut microbiota.
-
CASDH/CASDC orthologues are widespread in bacteria and cluster with putrescine-biosynthesis genes, consistent with spermidine synthesis.
"Orthologues encoding carboxyspermidine dehydrogenase and carboxyspermidine decarboxylase are found clustered with an array of diverse putrescine biosynthetic genes in different bacterial genomes, consistent with a role in spermidine, rather than sym-norspermidine biosynthesis."
Manual evidence notes for PP_2928
OpenScientist functional review of PP_2928
-
The completed retrieval supports CASDH assignment from family, synteny, pathway completeness, and comparative literature.
New routes for spermine biosynthesis.
-
Some related CASDH/CASDC pairs support tetramine or agmatine-dependent chemistry; this cautions against assigning substrate preference from family membership alone. No such additional activity is assigned here.
"The ASA-dependent pathway consisting of CASDH/CASDC homologs has diversified during evolution to produce norspermidine (29), N1-aminopropylagmatine (37), and as we have shown here, spermidine and Spm/Tspm."
Kinetic and structural characterization of carboxyspermidine dehydrogenase of polyamine biosynthesis.
-
Comparative putrescine/DAP kinetic measurements exist for B. fragilis and C. leptum CASDH, but do not measure this target or test agmatine preference.
"These data suggest that both enzymes can use putrescine or DAP and thus produce carboxyspermidine or carboxynorspermidine."
A bacterial spermidine biosynthetic pathway via carboxyaminopropylagmatine.
-
The CAPA pathway establishes functional divergence among CASDH-like enzymes, so PP_2928 family membership is not by itself proof of native putrescine use.
"Many bacterial genomes encode homologs of CASDH and CASDC (13); however, the polyamine biosynthetic pathway in most of these bacteria remains unclear."