1BSF

THERMOSTABLE THYMIDYLATE SYNTHASE A FROM BACILLUS SUBTILIS

1BSF の概要

• エントリーDOI: 10.2210/pdb1bsf/pdb
• 分子名称: THYMIDYLATE SYNTHASE A (1 entity in total)
• 機能のキーワード: methyltransferase, dtmp synthase
• 由来する生物種: Bacillus subtilis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 65433.96

構造登録者

Stout, T.J.,Schellenberger, U.,Santi, D.V.,Stroud, R.M. (登録日: 1998-07-10, 公開日: 1999-01-13, 最終更新日: 2024-05-22)

主引用文献

Stout, T.J.,Schellenberger, U.,Santi, D.V.,Stroud, R.M.
Crystal structures of a unique thermal-stable thymidylate synthase from Bacillus subtilis.
Biochemistry, 37:14736-14747, 1998

PubMed Abstract: Unlike all other organisms studied to date, Bacillus subtilis expresses two different thymidylate synthases: bsTS-A and bsTS-B. bsTS-A displays enhanced enzymatic and structural thermal stability uncharacteristic of most TSs. Despite the high level of TS conservation across most species, bsTS-A shares low sequence identity (<40%) with the majority of TSs from other organisms. This TS and the TSs from Lactococcus lactis and phage Phi3T-to which it is most similar-have been of interest for some time since, by structure-based sequence alignment, they appear to lack several key residues shown by mutagenesis to be essential to enzymatic function [Greene, P. J., Yu, P. L., Zhao, J., Schiffer, C. A., and Santi, D. (1994) Protein Sci. 3, 1114-6]. In addition, bsTS-A demonstrates specific activity 2-3-fold higher than TS from Lactobacillus casei or Escherichia coli. We have solved the crystal structure of this unusual TS in four crystal forms to a maximum resolution of 1.7 A. Each of these crystal forms contains either one or two noncrystallographically related dimers. Stabilization of the beta-sheet dimer interface through a dramatic architecture of buttressed internal salt bridges maintains the structural integrity of bsTS-A at elevated temperatures. Melting curves of TSs from L. casei and E. coli are compared to that of TS-A from B. subtilis and correlated with numbers of hydrogen bonds, salt bridges, and the numbers of interactions localized to the dimer interface. Analysis of this structure will shed light on the conservation of function across diversity of sequence, as well as provide insights into the thermal stabilization of a highly conserved enzyme.

PubMed: 9778348
DOI: 10.1021/bi981270l

実験手法

X-RAY DIFFRACTION (2.2 Å)