H227A 突变精氨酸激酶的晶体结构提示其稳定性的重要性。
Crystal Structure of H227A Mutant of Arginine Kinase in Suggests the Importance of Its Stability.
机构信息
Division of Biotechnology, College of Environmental & Bioresources Sciences, Jeonbuk National University, Iksan 54596, Korea.
Department of Lifestyle Medicine, College of Environmental and Bioresource Sciences, Jeonbuk National University, Iksan 54596, Korea.
出版信息
Molecules. 2022 Jan 28;27(3):884. doi: 10.3390/molecules27030884.
Arginine kinase (AK) plays a crucial role in the survival of , a water flea and a common planktonic invertebrate sensitive to water pollution, owing to the production of bioenergy. AK from (AK) has four highly conserved histidine residues, namely, H90, H227, H284, and H315 in the amino acid sequence. In contrast to AK WT (wild type), the enzyme activity of the H227A mutant decreases by 18%. To identify the structure-function relationship of this H227A mutant enzyme, the crystal 3D X-ray structure has been determined and an unfolding assay using anilino-1-naphthalenesulfonic acid (ANS) fluorescence has been undertaken. The results revealed that when compared to the AK WT, the hydrogen bonding between H227 and A135 was broken in the H227A crystal structure. This suggests that H227 residue, closed to the arginine binding site, plays an important role in maintaining the structural stability and maximizing the enzyme activity through hydrogen bonding with the backbone oxygen of A135.
精氨酸激酶（AK）在水生昆虫和常见的浮游无脊椎动物的生存中起着至关重要的作用，因为它能产生生物能量。 （AK）的 AK 具有四个高度保守的组氨酸残基，即氨基酸序列中的 H90、H227、H284 和 H315。与 AK WT（野生型）相比，H227A 突变酶的酶活性降低了 18%。为了确定该 H227A 突变酶的结构-功能关系，已经确定了其晶体 3D X 射线结构，并使用对氨基苯磺酰荧光素（ANS）荧光进行了展开测定。结果表明，与 AK WT 相比，H227A 晶体结构中 H227 与 A135 之间的氢键被打破。这表明，靠近精氨酸结合位点的 H227 残基通过与 A135 的骨架氧形成氢键，在维持结构稳定性和使酶活性最大化方面发挥着重要作用。
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