3PGA

STRUCTURAL CHARACTERIZATION OF PSEUDOMONAS 7A GLUTAMINASE-ASPARAGINASE

3PGA の概要

• エントリーDOI: 10.2210/pdb3pga/pdb
• 分子名称: GLUTAMINASE-ASPARAGINASE (2 entities in total)
• 機能のキーワード: bacterial amidohydrolase
• 由来する生物種: Pseudomonas sp. 7A
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 143914.64

構造登録者

Lubkowski, J.,Wlodawer, A.,Ammon, H.L.,Copeland, T.D.,Swain, A.L. (登録日: 1994-07-19, 公開日: 1994-12-20, 最終更新日: 2024-02-21)

主引用文献

Lubkowski, J.,Wlodawer, A.,Ammon, H.L.,Copeland, T.D.,Swain, A.L.
Structural characterization of Pseudomonas 7A glutaminase-asparaginase.
Biochemistry, 33:10257-10265, 1994

PubMed Abstract: The amino acid sequence and a 2-A-resolution crystallographic structure of Pseudomonas 7A glutaminase-asparaginase (PGA) have been determined. PGA, which belongs to the family of tetrameric bacterial amidohydrolases, deamidates glutamine and asparagine. The amino acid sequence of PGA has a high degree of similarity to the sequences of other members of the family. PGA has the same fold as other bacterial amidohydrolases, with the exception of the position of a 20-residue loop that forms part of the active site. In the PGA structure presented here, the active site loop is observed clearly in only one monomer, in an open position, with a conformation different from that observed for other amidohydrolases. In the other three monomers the loop is disordered and cannot be traced. This phenomenon is probably a direct consequence of a very low occupancy of product(s) of the enzymatic reaction bound in the active sites of PGA in these crystals. The active sites are composed of a rigid part and the flexible loop. The rigid part consists of the residues directly involved in the catalytic reaction as well as residues that assist in orienting the substrate. Two residues that are important for activity residue on the flexible loop. We suggest that the flexible loops actively participate in the transport of substrate and product molecules through the amidohydrolase active sites and participate in orienting the substrate molecules properly in relation to the catalytic residues.

PubMed: 8068664
DOI: 10.1021/bi00200a005

実験手法

X-RAY DIFFRACTION (2 Å)