7QOU

A mutant of the nitrile hydratase from Geobacillus pallidus having enhanced thermostability

7QOU の概要

• エントリーDOI: 10.2210/pdb7qou/pdb
• 分子名称: Nitrile hydratase, Nitrile hydratase subunit beta, COBALT (II) ION, ... (6 entities in total)
• 機能のキーワード: heterotetramer, lyase
• 由来する生物種: Aeribacillus pallidus; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 51405.38

構造登録者

Van Wyk, J.C.,Cowan, D.A.,Danson, M.J.,Tsekoa, T.L.,Sayed, M.F.,Sewell, B.T. (登録日: 2021-12-29, 公開日: 2023-01-18, 最終更新日: 2024-10-23)

主引用文献

Van Wyk, J.C.,Sewell, B.T.,Danson, M.J.,Tsekoa, T.L.,Sayed, M.F.,Cowan, D.A.
Engineering enhanced thermostability into the Geobacillus pallidus nitrile hydratase.
Curr Res Struct Biol, 4:256-270, 2022

PubMed Abstract: Nitrile hydratases (NHases) are important biocatalysts for the enzymatic conversion of nitriles to industrially-important amides such as acrylamide and nicotinamide. Although thermostability in this enzyme class is generally low, there is not sufficient understanding of its basis for rational enzyme design. The gene expressing the Co-type NHase from the moderate thermophile, RAPc8 (NRRL B-59396), was subjected to random mutagenesis. Four mutants were selected that were 3 to 15-fold more thermostable than the wild-type NHase, resulting in a 3.4-7.6 ​kJ/mol increase in the activation energy of thermal inactivation at 63 ​°C. High resolution X-ray crystal structures (1.15-1.80 ​Å) were obtained of the wild-type and four mutant enzymes. Mutant 9E, with a resolution of 1.15 ​Å, is the highest resolution crystal structure obtained for a nitrile hydratase to date. Structural comparisons between the wild-type and mutant enzymes illustrated the importance of salt bridges and hydrogen bonds in enhancing NHase thermostability. These additional interactions variously improved thermostability by increased intra- and inter-subunit interactions, preventing cooperative unfolding of α-helices and stabilising loop regions. Some hydrogen bonds were mediated via a water molecule, specifically highlighting the significance of structured water molecules in protein thermostability. Although knowledge of the mutant structures makes it possible to rationalize their behaviour, it would have been challenging to predict in advance that these mutants would be stabilising.

PubMed: 36106339
DOI: 10.1016/j.crstbi.2022.07.002

実験手法

X-RAY DIFFRACTION (1.3 Å)