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Structure‐based investigation into the functional roles of the extended loop and substrate‐recognition sites in an endo‐β‐1,4‐ d ‐mannanase from the Antarctic springtail, Cryptopygus antarcticus
Author(s) -
Kim MinKyu,
An Young Jun,
Song Jung Min,
Jeong ChangSook,
Kang Mee Hye,
Kwon Kae Kyoung,
Lee YounHo,
Cha SunShin
Publication year - 2014
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.24655
Subject(s) - substrate (aquarium) , multicellular organism , biology , loop (graph theory) , enzyme , chemistry , stereochemistry , biochemistry , ecology , mathematics , gene , combinatorics
Endo‐β‐1,4‐ d ‐mannanase from the Antarctic springtail, Cryptopygus antarcticus ( Ca Man), is a cold‐adapted β‐mannanase that has the lowest optimum temperature (30°C) of all known β‐mannanases. Here, we report the apo‐ and mannopentaose (M5) complex structures of Ca Man. Structural comparison of Ca Man with other β‐mannanases from the multicellular animals reveals that Ca Man has an extended loop that alters topography of the active site. Structural and mutational analyses suggest that this extended loop is linked to the cold‐adapted enzymatic activity. From the Ca Man‐M5 complex structure, we defined the mannose‐recognition subsites and observed unreported M5 binding site on the surface of Ca Man. Proteins 2014; 82:3217–3223. © 2014 Wiley Periodicals, Inc.