5FAC

Alanine Racemase from Streptomyces coelicolor A3(2)

5FAC の概要

• エントリーDOI: 10.2210/pdb5fac/pdb
• 分子名称: Alanine racemase, PYRIDOXAL-5'-PHOSPHATE, CHLORIDE ION, ... (4 entities in total)
• 機能のキーワード: isomerase, plp, alanine racemase
• 由来する生物種: Streptomyces coelicolor A3(2)
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 174626.14

構造登録者

Tassoni, R.,Pannu, N.S. (登録日: 2015-12-11, 公開日: 2016-12-21, 最終更新日: 2024-01-10)

主引用文献

Tassoni, R.,van der Aart, L.T.,Ubbink, M.,van Wezel, G.P.,Pannu, N.S.
Structural and functional characterization of the alanine racemase from Streptomyces coelicolor A3(2).
Biochem. Biophys. Res. Commun., 483:122-128, 2017

PubMed Abstract: The conversion of l-alanine (L-Ala) into d-alanine (D-Ala) in bacteria is performed by pyridoxal phosphate-dependent enzymes called alanine racemases. D-Ala is an essential component of the bacterial peptidoglycan and hence required for survival. The Gram-positive bacterium Streptomyces coelicolor has at least one alanine racemase encoded by alr. Here, we describe an alr deletion mutant of S. coelicolor which depends on D-Ala for growth and shows increased sensitivity to the antibiotic d-cycloserine (DCS). The crystal structure of the alanine racemase (Alr) was solved with and without the inhibitors DCS or propionate, at 1.64 Å and 1.51 Å resolution, respectively. The crystal structures revealed that Alr is a homodimer with residues from both monomers contributing to the active site. The dimeric state of the enzyme in solution was confirmed by gel filtration chromatography, with and without L-Ala or d-cycloserine. The activity of the enzyme was 66 ± 3 U mg for the racemization of L- to D-Ala, and 104 ± 7 U mg for the opposite direction. Comparison of Alr from S. coelicolor with orthologous enzymes from other bacteria, including the closely related d-cycloserine-resistant Alr from S. lavendulae, strongly suggests that structural features such as the hinge angle or the surface area between the monomers do not contribute to d-cycloserine resistance, and the molecular basis for resistance therefore remains elusive.

PubMed: 28042035
DOI: 10.1016/j.bbrc.2016.12.183

実験手法

X-RAY DIFFRACTION (2.8 Å)