超好熱性古細菌Thermococcus litoralis由来4-α-グルカノトランスフェラーゼの反応機構と構造解析  [in Japanese] Reaction Mechanism and Crystal Structure of 4-α-Glucanotransferase from a Hyperthermophilic Archaeon, Thermococcus litoralis  [in Japanese]

Access this Article

Search this Article

Author(s)

Abstract

Thermococcus litoralis 4-α-glucanotransferase (GTase) belongs to family 57 of glycosyl hydro-lases and catalyzes the disproportionation and cycloamylose synthesis reactions. Using 3-ketobutylidene-β-2-chloro-4-nitrophenyl-maltopentaoside (3 KBG 5 CNP) as a donor and glucose as an acceptor, we showed that the disproportionation reaction of 4-α-glucanotransferase involves a Ping-Pong Bi Bi mechanism. Based on this reaction mechanism, we trapped the glycosyl-enzyme intermediate by treating the enzyme with 3 KBG 5 CNP in the absence of an acceptor. MALDITOFMS and PSD analysis of a peptic digest of the intermediate and great decrease in activity of the E 123 Q mutant enzyme indicated that completely conserved Glu 123 was the catalytic amino acid. Next, we have determined the structure of GTase, the first structure of the family 57 of glycosyl hydrolases, at 2.8 Å resolution. The structure of GTase is composed of three domains. N-terminal domain (domain A) contains two catalytic residues and has a novel pseudo-TIM barrel fold. C-terminal domain (domain C) is mainly made of β-strands arranged in two layered β-sheet sandwich. Domain B is located between domains A and C, and consists of α- and 3<SUB>10</SUB>-helices. Active site cleft lies between domains A and B. The cleft is partially covered with aromatic residues to form a tunnel-like shape, which probably plays an important role in the formation of large cyclic glucans.

Journal

  • Journal of Applied Glycoscience

    Journal of Applied Glycoscience 48(2), 171-175, 2001-04-01

    The Japanese Society of Applied Glycoscience

References:  13

Cited by:  3

Codes

  • NII Article ID (NAID)
    10008252642
  • NII NACSIS-CAT ID (NCID)
    AN10453916
  • Text Lang
    JPN
  • Article Type
    Journal Article
  • ISSN
    13403494
  • NDL Article ID
    5764783
  • NDL Source Classification
    ZP24(科学技術--化学・化学工業--糖・澱粉)
  • NDL Call No.
    Z17-15
  • Data Source
    CJP  CJPref  NDL  J-STAGE 
Page Top