A circularly permuted α‐amylase‐type α/β‐barrel structure in glucan‐synthesizing glucosyltransferases

FEBS Letters

Svensson, Birte²  MacGregor, E.Ann³  Jespersen, Hans M.¹ 

[1] Department of Protein Chemistry, University of Copenhagen, DK-1353 Copenhagen, Denmark;Department of Chemistry, Carlsberg Laboratory, Gamle Carlsberg Vej 10, DK-2500 Copenhagen Valby, Denmark;Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada

关键词: α-Amylase protein superfamily;    Circular permutation;    Glucosyltransferase;    Parallel α/β-barrel;    Structure prediction;    CGTase;    cyclodextrin glucosytransferase;    El;    E2;    E8;    β-strands of the (β/α)8-barrel;    G4ase;    maltotetraose-producing amylase;    GTF-I;    glucosyltransferase that synthesizes insoluble glucan (socalled mutan);    GTF-S;    glucosyltransferase that synthesizes soluble dextran;    H1;    H2;    H8;    helices of the (β/α)8-barrel;    MBC/C;    minimum base change per codon;    TAA;    Taka-amylase A;   

DOI  :  10.1016/0014-5793(95)01428-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

A motif of amino acid residues, located at the active site and specific β-strands in a-amylases, is recognized in α-1,3- and α-1,6-glucan-synthesizing glucosyltransferases, leading to the conclusion that these enzymes contain an α/β-barrel closely related to the (β/α)₈-fold of the α-amylase superfamily. The secondary structure elements of the transferase barrel, however, are circularly permuted to start with an α-helix equivalent to helix 3 in the α-amylases. Thus, the transferase counterpart of the long third β → α connection — constituting a domain in the α-amylases — is divided to precede and succeed the barrel. This architectural arrangement may be coupled to sucrose scission and glucosyl transfer. The involvement in the mechanism in glucosyltransferases of active site residues recurring in amylolytic enzymes is discussed.

【 授权许可】

Unknown