4U3A

Crystal structure of CtCel5E

Summary for 4U3A

• Entry DOI: 10.2210/pdb4u3a/pdb
• Related: 4U5I 4U5K
• Descriptor: Endoglucanase H (2 entities in total)
• Functional Keywords: bi-functional cellulase/xylanase, hydrolase
• Biological source: Clostridium thermocellum ATCC 27405
• Total number of polymer chains: 2
• Total formula weight: 92500.90

Authors

Yuan, S.F.,Liang, P.H.,Ho, M.C. (deposition date: 2014-07-19, release date: 2015-01-14, Last modification date: 2024-03-20)

Primary citation

Yuan, S.F.,Wu, T.H.,Lee, H.L.,Hsieh, H.Y.,Lin, W.L.,Yang, B.,Chang, C.K.,Li, Q.,Gao, J.,Huang, C.H.,Ho, M.C.,Guo, R.T.,Liang, P.H.
Biochemical Characterization and Structural Analysis of a Bifunctional Cellulase/Xylanase from Clostridium thermocellum
J.Biol.Chem., 290:5739-5748, 2015

PubMed Abstract: We expressed an active form of CtCel5E (a bifunctional cellulase/xylanase from Clostridium thermocellum), performed biochemical characterization, and determined its apo- and ligand-bound crystal structures. From the structures, Asn-93, His-168, His-169, Asn-208, Trp-347, and Asn-349 were shown to provide hydrogen-bonding/hydrophobic interactions with both ligands. Compared with the structures of TmCel5A, a bifunctional cellulase/mannanase homolog from Thermotoga maritima, a flexible loop region in CtCel5E is the key for discriminating substrates. Moreover, site-directed mutagenesis data confirmed that His-168 is essential for xylanase activity, and His-169 is more important for xylanase activity, whereas Asn-93, Asn-208, Tyr-270, Trp-347, and Asn-349 are critical for both activities. In contrast, F267A improves enzyme activities.

PubMed: 25575592
DOI: 10.1074/jbc.M114.604454

Experimental method

X-RAY DIFFRACTION (2.42 Å)