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Crystal structure of non‐allosteric L ‐lactate dehydrogenase from Lactobacillus pentosus at 2.3 Å resolution: Specific interactions at subunit interfaces
Author(s) -
Uchikoba Hiroyuki,
Fushinobu Shinya,
Wakagi Takayoshi,
Konno Michiko,
Taguchi Hayao,
Matsuzawa Hiroshi
Publication year - 2001
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.1165
Subject(s) - allosteric regulation , lactate dehydrogenase , protein subunit , resolution (logic) , chemistry , biology , biochemistry , enzyme , gene , computer science , artificial intelligence
L ‐Lactate dehydrogenase (LDH) from Lactobacillus pentosus is a non‐allosteric enzyme, which shows, however, high sequence similarity to allosteric LDHs from certain bacteria. To elucidate the structural basis of the absence of allostery of L. pentosus LDH (LPLDH), we determined the crystal structure of LPLDH at 2.3 Å resolution. Bacterial LDHs are tetrameric enzymes composed of identical subunits and exhibit 222 symmetry. The quaternary structure of LPLDH was similar to the active conformation of allosteric LDHs. Structural analysis revealed that the subunit interfaces of LPLDH are optimized mainly through hydrophilic interactions rather than hydrophobic interactions, compared with other LDHs. The subunit interfaces of LPLDH are more specifically stabilized by increased numbers of intersubunit salt bridges and hydrogen bonds, and higher geometrical complementarity. Such high specificity at the subunit interfaces should hinder the rearrangement of the quaternary structure needed for allosteric regulation and thus explain the “non‐allostery” of LPLDH. Proteins 2002;46:206–214. © 2001 Wiley‐Liss, Inc.