GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

CelK carries GH9 (IPR001701) and CBM4 InterPro signatures, which drive InterPro2GO inferences of carbohydrate metabolism and cellulase activity at the family level (more specific cellobiohydrolase activity is captured by the EC mapping).

GO_REF:0000003

Gene Ontology annotation based on Enzyme Commission mapping

EC 3.2.1.91 (cellulose 1,4-beta-cellobiosidase) maps to GO:0016162, the most specific molecular-function term for CelK.

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

UniProtKB keyword KW-0136 (Cellulose degradation) maps to GO:0030245 (cellulose catabolic process).
UniProtKB keyword KW-0378 (Hydrolase) maps to GO:0016787 (hydrolase activity).

GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

UniProt Subcellular Location "Secreted" maps to GO:0005576 (extracellular region); for CelK the more specific GO:0043263 (cellulosome) is preferred because the protein bears a type I dockerin and integrates into the cellulosome.

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

Combined evidence sources (InterPro2GO, ARBA, UniRule) converge on glycosyl hydrolase activity acting on O-glycosyl compounds and polysaccharide catabolism for this GH9 dockerin-bearing cellobiohydrolase.

PMID:29075324

Comparative characterization of all cellulosomal cellulases from Clostridium thermocellum reveals high diversity in endoglucanase product formation essential for complex activity.

Cel9K is classified as a cellobiohydrolase (CBH) in Table 1

"Cel9K0412GH9Inverting"
CBHs including Cel9K release cellobiose as the main product

"CBHs (exo-acting from the sugar ends) released specifically cellobiose as the only product over time (Cel48S, Cel9K, and Cbh9A)"
Cel9K shows weak activity on modified substrates but substantial activity on PASC

"As expected, for the CBHs Cbh9A, Cel48S, and Cel9K no or very weak activities on modified substrates were observed, whereas on PASC substantial product formation was found"

PMID:16127726

Functional subgenomics of Clostridium thermocellum cellulosomal genes: identification of the major catalytic components in the extracellular complex and detection of three new enzymes.

Cel9K is identified as a major cellulosomal cellobiohydrolase

"the cellobiohydrolases Cbh9A, Cel9K, Cel48S"

PMID:17644599

Global view of the Clostridium thermocellum cellulosome revealed by quantitative proteomic analysis

CelK shows higher expression in cellulosomes from cellulose-grown cells

"exoglucanases CelS and CelK"

file:ACET2/celK/celK-deep-research-falcon.md

Deep research literature review for celK

CelK identity confirmed as Cel9K with locus Cthe_0412

"The target is celK from Acetivibrio thermocellus (Clostridium thermocellum). Comparative catalogs and proteomics explicitly map CelK to Cel9K with locus tag Cthe_0412"
CelK is a cellulosomal subunit with type-I dockerin

"CelK is a secreted, extracellular cellulosomal subunit that incorporates into the cellulosome via type-I dockerin interactions"
CelK belongs to GH9 family with inverting mechanism

"CelK belongs to glycoside hydrolase family 9 (GH9), which utilize an inverting catalytic mechanism"