9HIT

Structure of P167S/D240G BlaC from Mycobacterium tuberculosis

9HIT の概要

• エントリーDOI: 10.2210/pdb9hit/pdb
• 分子名称: Beta-lactamase, CITRIC ACID (3 entities in total)
• 機能のキーワード: beta lactamase, hydrolase
• 由来する生物種: Mycobacterium tuberculosis
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 28467.85

構造登録者

Sun, J.,Bruenle, S.,Ubbink, M. (登録日: 2024-11-27, 公開日: 2025-10-22)

主引用文献

Sun, J.,Timmer, M.,Brunle, S.,Boyle, A.L.,Ubbink, M.
Directed evolution of a beta-lactamase samples a wide variety of conformational states.
Protein Sci., 34:e70322-e70322, 2025

PubMed Abstract: In directed evolution, enzyme activity is improved in successive generations of laboratory evolution, which can be described by a simple stepwise climb toward a peak in the fitness landscape. In a naive model of evolution, it can be assumed that each enzyme variant along this path is in a single, well-defined state that differs slightly from the previous one. We analyzed the structural changes in mutants of the β-lactamase BlaC from Mycobacterium tuberculosis obtained via directed evolution for increased ceftazidime hydrolysis activity. Crystal structures of three successive mutants only show an increase in the dynamics of a loop that lines the active site (Ω-loop), enabling better access of the large substrate. However, NMR spectra of wild type and nine mutants of different branches of the directed evolution experiment show a much more diverse and complex picture of the conformational effects. Many mutants show micro-millisecond dynamics for certain regions and most show peak doubling, indicative of two or more conformations being populated. Thus, the straightforward climb to increased ceftazidime activity in the fitness landscape masks a complex trajectory in the conformational landscape, emphasizing the complex and epistatic interplay that single mutations can have on the structure and dynamics of enzymes.

PubMed: 41074874
DOI: 10.1002/pro.70322

実験手法

X-RAY DIFFRACTION (1.3 Å)