3R4C

Divergence of Structure and Function Among Phosphatases of the Haloalkanoate (HAD) Enzyme Superfamily: Analysis of BT1666 from Bacteroides thetaiotaomicron

3R4C の概要

• エントリーDOI: 10.2210/pdb3r4c/pdb
• 分子名称: Hydrolase, haloacid dehalogenase-like hydrolase, MAGNESIUM ION, SULFATE ION, ... (4 entities in total)
• 機能のキーワード: haloalkanoate dehalogenase enzyme superfamily, phosphohydrolase, hydrolase
• 由来する生物種: Bacteroides thetaiotaomicron
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 29270.67

構造登録者

Allen, K.N.,Lu, Z.,Dunaway-Mariano, D. (登録日: 2011-03-17, 公開日: 2011-10-26, 最終更新日: 2023-09-13)

主引用文献

Lu, Z.,Dunaway-Mariano, D.,Allen, K.N.
The X-ray crystallographic structure and specificity profile of HAD superfamily phosphohydrolase BT1666: Comparison of paralogous functions in B. thetaiotaomicron.
Proteins, 79:3099-3107, 2011

PubMed Abstract: Analysis of the haloalkanoate dehalogenase superfamily (HADSF) has uncovered homologues occurring within the same organism that are found to possess broad, overlapping substrate specificities, and low catalytic efficiencies. Here we compare the HADSF phosphatase BT1666 from Bacteroides thetaiotaomicron VPI-5482 to a homologue with high sequence identity (40%) from the same organism BT4131, a known hexose-phosphate phosphatase. The goal is to find whether these enzymes represent duplicated versus paralogous activities. The X-ray crystal structure of BT1666 was determined to 1.82 Å resolution. Superposition of the BT1666 and BT4131 structures revealed a conserved fold and identical active sites suggestive of a common physiological substrate. The steady-state kinetic constants for BT1666 were determined for a diverse panel of phosphorylated metabolites to define its substrate specificity profile and overall level of catalytic efficiency. Whereas BT1666 and BT4131 are both promiscuous, their substrate specificity profiles are distinct. The catalytic efficiency of BT1666 (k(cat) /K(m) = 4.4 × 10(2) M(-1) s(-1) for the best substrate fructose 1,6-(bis)phosphate) is an order of magnitude less than that of BT4131 (k(cat) /K(m) = 6.7 × 10(3) M(-1) s(-1) for 2-deoxyglucose 6-phosphate). The seemingly identical active-site structures point to sequence variation outside the active site causing differences in conformational dynamics or subtle catalytic positioning effects that drive the divergence in catalytic efficiency and selectivity. The overlapping substrate profiles may be understood in terms of differential regulation of expression of the two enzymes or a conferred advantage in metabolic housekeeping functions by having a larger range of possible metabolites as substrates.

PubMed: 21989931
DOI: 10.1002/prot.23137

実験手法

X-RAY DIFFRACTION (1.82 Å)