{PDOC00511} {PS60032; GH9_1} {PS00592; GH9_2} {PS00698; GH9_3} {BEGIN} ************************************************************** * Glycosyl hydrolases family 9 (GH9) active sites signatures * ************************************************************** The microbial degradation of cellulose and xylans requires several types of enzymes such as endoglucanases (EC 3.2.1.4), cellobiohydrolases (EC 3.2.1.91) (exoglucanases), or xylanases (EC 3.2.1.8) [1,2]. Fungi and bacteria produces a spectrum of cellulolytic enzymes (cellulases) and xylanases which, on the basis of sequence similarities, can be classified into families. One of these families is known as the cellulase family E [3] or as the glycosyl hydrolases family 9 [4,E1]. The enzymes which are currently known to belong to this family are widely distributed among bacteria, fungi, amoebozoa, invertebrate metazoans, mosses, ferns, gymnosperms, and angiosperms: - Butyrivibrio fibrisolvens cellodextrinase 1 (ced1). - Cellulomonas fimi endoglucanases B (cenB) and C (cenC). - Clostridium cellulolyticum endoglucanase G (celCCG). - Clostridium cellulovorans endoglucanase C (engC). - Clostridium stercoararium endoglucanase Z (avicelase I) (celZ). - Clostridium thermocellum endoglucanases D (celD), F (celF) and I (celI). - Fibrobacter succinogenes endoglucanase A (endA). - Pseudomonas fluorescens endoglucanase A (celA). - Streptomyces reticuli endoglucanase 1 (cel1). - Thermomonospora fusca endoglucanase E-4 (celD). - Dictyostelium discoideum spore germination specific endoglucanase 270-6. This slime mold enzyme may digest the spore cell wall during germination, to release the enclosed amoeba. - Endoglucanases from unicellular green microalgae, such as the unicellular alga Chlamydomonas reinhardtii or the colonial algae Gonium pectorale and Volvox carteri. Microalgae can utilize cellulose for growth in the absence/ limitation of other C-sources by secreting endocellulases. - Endoglucanases from plants such as Avocado or French bean. In plants this enzyme may be involved in the fruit ripening process. - Invertebrate endoglucanases, secreted by salivary glands and the gut. Three conserved regions in these enzymes are centered on conserved residues which have been shown [5,6,7] to be important for the catalytic activity. The first region contains the characteristic DAGD motif, where the C-terminal D acts as the catalytic base that extracts a proton from the nucleophilic water. The second region contains an active site histidine and the third one contains two catalytically important residues: an aspartate and a glutamate. The fully conserved nucleophilic D forms H-bonds with the residues of the active-site loop, comprising of regions I and II, to bring it in the proper alignement. The fully conserved E acts as an acid that protonates the leaving group and stabilizes the positively-charged oxocarbonium transition-state. We have used these three regions as signature patterns, with the first pattern corresponding to region I, the second to region II and the third to region III. -Consensus pattern: [LVS]-x-[GK]-G-[WFYLM]-[YHF]-D-[ACGS]-G-[DSN]-x(2)-[KMR]- [FAILY]-x-[FWYLQTV]-[APTNS]-[MLGAQS] [The C-terminal D is an active site residue] -Sequences known to belong to this class detected by the pattern: ALL, except two partial sequences. -Other sequence(s) detected in Swiss-Prot: NONE. -Consensus pattern: [HLY]-[AILMV]-[FIL]-G-x-[NSTW]-x(2,4)-[SCTV]-[FY]- [LIVMFY]-[SITV]-G-x(1,5)-[GSY]-x(2)-[AFPSTY]-[FLPSV]-x(2)- [AILPQVM]-[HV]-[DHLS]-[KRS] [H is an active site residue] -Sequences known to belong to this class detected by the pattern: ALL. one partial sequence. -Other sequence(s) detected in Swiss-Prot: NONE. -Consensus pattern: [FYW]-x-D-x(4)-[FYW]-x(3)-E-x-[STA]-x(3)-N-[STA] [D and E are active site residues] -Sequences known to belong to this class detected by the pattern: ALL, except for Fibrobacter succinogenes endA whose sequence seems to be incorrect. -Other sequence(s) detected in Swiss-Prot: 2. -Expert(s) to contact by email: Siddiqui K.S.; ksiddiqui@kfupm.edu.sa Henrissat B.; bernie@afmb.cnrs-mrs.fr -Last update: November 2018 / Text and old pattern revised; new pattern added. [ 1] Beguin P. "Molecular biology of cellulose degradation." Annu. Rev. Microbiol. 44:219-248(1990). PubMed=2252383; DOI=10.1146/annurev.mi.44.100190.001251 [ 2] Gilkes N.R., Henrissat B., Kilburn D.G., Miller R.C. Jr., Warren R.A.J. "Domains in microbial beta-1, 4-glycanases: sequence conservation, function, and enzyme families." Microbiol. Rev. 55:303-315(1991). PubMed=1886523 [ 3] Henrissat B., Claeyssens M., Tomme P., Lemesle L., Mornon J.-P. "Cellulase families revealed by hydrophobic cluster analysis." Gene 81:83-95(1989). PubMed=2806912 [ 4] Henrissat B. "A classification of glycosyl hydrolases based on amino acid sequence similarities." Biochem. J. 280:309-316(1991). PubMed=1747104 [ 5] Tomme P., Chauvaux S., Beguin P., Millet J., Aubert J.-P., Claeyssens M. "Identification of a histidyl residue in the active center of endoglucanase D from Clostridium thermocellum." J. Biol. Chem. 266:10313-10318(1991). PubMed=2037583 [ 6] Tomme P., van Beeumen J., Claeyssens M. "Modification of catalytically important carboxy residues in endoglucanase D from Clostridium thermocellum." Biochem. J. 285:319-324(1992). PubMed=1637316 [ 7] Guerriero G., Sergeant K., Legay S., Hausman J.-F., Cauchie H.-M., Ahmad I., Siddiqui K.S. "Novel Insights from Comparative In Silico Analysis of Green Microalgal Cellulases." Int. J. Mol. Sci. 19:0-0(2018). PubMed=29914107; DOI=10.3390/ijms19061782 [E1] https://www.uniprot.org/docs/glycosid -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}