3VTR

Crystal Structure of insect beta-N-acetyl-D-hexosaminidase OfHex1 E328A complexed with TMG-chitotriomycin

3VTR の概要

• エントリーDOI: 10.2210/pdb3vtr/pdb
• 関連するPDBエントリー: 3NSM 3NSN
• 関連するBIRD辞書のPRD_ID: PRD_900080
• 分子名称: N-acetylglucosaminidase, 2-deoxy-2-(trimethylammonio)-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose, ... (4 entities in total)
• 機能のキーワード: insect, chitin, beta-n-acetyl-d-hexosaminidase, tmg-chitotriomycin, hydrolase-antibiotic complex, hydrolase/antibiotic
• 由来する生物種: Ostrinia furnacalis (Asian corn borer)
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 66769.07

構造登録者

Liu, T.,Zhou, Y.,Chen, L.,Chen, W.,Liu, L.,Shen, X.,Yang, Q. (登録日: 2012-06-02, 公開日: 2013-01-16, 最終更新日: 2024-10-09)

主引用文献

Liu, T.,Zhou, Y.,Chen, L.,Chen, W.,Liu, L.,Shen, X.,Zhang, W.,Zhang, J.,Yang, Q.
Structural insights into cellulolytic and chitinolytic enzymes revealing crucial residues of insect beta-N-acetyl-D-hexosaminidase
Plos One, 7:e52225-e52225, 2012

PubMed Abstract: The chemical similarity of cellulose and chitin supports the idea that their corresponding hydrolytic enzymes would bind β-1,4-linked glucose residues in a similar manner. A structural and mutational analysis was performed for the plant cellulolytic enzyme BGlu1 from Oryza sativa and the insect chitinolytic enzyme OfHex1 from Ostrinia furnacalis. Although BGlu1 shows little amino-acid sequence or topological similarity with OfHex1, three residues (Trp(490), Glu(328), Val(327) in OfHex1, and Trp(358), Tyr(131) and Ile(179) in BGlu1) were identified as being conserved in the +1 sugar binding site. OfHex1 Glu(328) together with Trp(490) was confirmed to be necessary for substrate binding. The mutant E328A exhibited a 8-fold increment in K(m) for (GlcNAc)(2) and a 42-fold increment in K(i) for TMG-chitotriomycin. A crystal structure of E328A in complex with TMG-chitotriomycin was resolved at 2.5 Å, revealing the obvious conformational changes of the catalytic residues (Glu(368) and Asp(367)) and the absence of the hydrogen bond between E328A and the C3-OH of the +1 sugar. V327G exhibited the same activity as the wild-type, but acquired the ability to efficiently hydrolyse β-1,2-linked GlcNAc in contrast to the wild-type. Thus, Glu(328) and Val(327) were identified as important for substrate-binding and as glycosidic-bond determinants. A structure-based sequence alignment confirmed the spatial conservation of these three residues in most plant cellulolytic, insect and bacterial chitinolytic enzymes.

PubMed: 23300622
DOI: 10.1371/journal.pone.0052225

実験手法

X-RAY DIFFRACTION (2.5 Å)