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Query: KEGG:D03434 (Cellulase)
 512 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Caldocellum saccharolyticum is an extremely thermophilic anaerobic bacterium capable of growth on cellulose and hemicellulose as sole carbon sources. Cellulase and hemicellulase genes have been found clustered together on its genome. The gene for one of the cellulases (celA) was isolated on a lambda genomic library clone, sequenced and found to comprise a large open-reading frame of 5253 base pairs that could be translated into a peptide of 1751 amino acids. To date, it is the largest cellulase gene sequenced. The translated product is a multidomain structure composed of two catalytic domains and two cellulose-binding domains linked by proline-threonine-rich regions (PT linkers). The N-terminal domain of celA encodes for an endoglucanase activity on carboxymethylcellulose, consistent with its high homology to the sequences of several other endo-1, 4-beta-D-glucanases. The carboxyterminal domain shows sequence homology with a cellulase from Clostridium thermocellum (CelS), which is known to act synergistically with a second component to hydrolyze crystalline cellulose. In the absence of a Caldocellum homologue for this second protein, we can detect no activity from this domain.
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PMID:celA, another gene coding for a multidomain cellulase from the extreme thermophile Caldocellum saccharolyticum. 761 47

Cellulase is one of the most widely distributed enzymes with wide application. They are involved in conversion of biomass into simpler sugars. Cellulase of Trichoderma longibrachiatum, a known cellulolytic fungus was compared with Clostridium thermocellum [AAA23226.1] cellulase. Blastp was performed with AAA23226.1 as query sequence to obtain nine similar sequences from NCBI protein data bank. The physicochemical properties of cellulase were analyzed using ExPASy's ProtParam tool namely ProtParam, SOPMA and GOR IV. Homology modeling was done using SWISS MODEL and checked quality by RMSD values using VMD1.9.1. Active sites of each model were predicted using automated active site prediction server of SCFBio. Study revealed instability of cellulase of two eukaryotic strains namely Trichoderma longibrachiatum [CAA43059.1] and Melanocarpus albomyces [CAD56665.1]. The negative GRAVY score value of cellulases ensured better interaction and activity in aqueous phase. It was found that molecular weight (M. Wt) ranges between 25-127.56 kDa. Iso-electric point (pI) of cellulases was found to be acidic in nature. GOR IV and SOPMA were used to predict secondary structure of cellulase, which showed that random coil, was dominated. Neighbor joining tree with C. thermocellum [AAA23226.1] cellulase as root showed that cellulases of Thermoaerobacter subterraneus [ZP_07835928] and C. thermocellum [CAA4305.1] were more similar to eukaryotic cellulases supported by least boot strap values. Pseudoalteromonas haloplanktis cellulase was found to be the ideal model supported by least RMSD score among the predicted structures. Trichoderma longibrachiatum cellulase was found to be the best compared to other cellulases, which possess high number of active sites with ASN and THR rich active sites. CYS residues were also present ensuring stable interaction and better bonding. Hydrophilic residues were found high in active sites of all analyzed models and template.
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PMID:Modeling and structural analysis of cellulases using Clostridium thermocellum as template. 2325 Oct 45