1chk | pdb_00001chk
From Proteopedia
STREPTOMYCES N174 CHITOSANASE PH5.5 298K
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Structural highlights
Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe report the 2.4 A X-ray crystal structure of a protein with chitosan endo-hydrolase activity isolated from Streptomyces N174. The structure was solved using phases acquired by SIRAS from a two-site methyl mercury derivative combined with solvent flattening and non-crystallographic two-fold symmetry averaging, and refined to an R-factor of 18.5%. The mostly alpha-helical fold reveals a structural core shared with several classes of lysozyme and barley endochitinase, in spite of a lack of shared sequence. Based on this structural similarity we postulate a putative active site, mechanism of action and mode of substrate recognition. It appears that Glu 22 acts as an acid and Asp 40 serves as a general base to activate a water molecule for an SN2 attack on the glycosidic bond. A series of amino-acid side chains and backbone carbonyl groups may bind the polycationic chitosan substrate in a deep electronegative binding cleft. X-ray structure of an anti-fungal chitosanase from streptomyces N174.,Marcotte EM, Monzingo AF, Ernst SR, Brzezinski R, Robertus JD Nat Struct Biol. 1996 Feb;3(2):155-62. PMID:8564542[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||
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