Studies were conducted to understand the role of C-terminal lysine residues in the catalytic activity, structural stability and oligomeric properties of Staphylococcus aureus enolase. Interestingly, the S. aureus enolase, in solution, shows its presence as a stable dimer as well as the catalytically active fragile octamer. Compared to the hexa-histidine tagged S. aureus enolase (rSaeno), the deletion mutant showed the negligible difference in K_m, but approximately 20–25% reduction in maximum reaction velocity (V_max) and 2% reduction in turnover number were observed. These kinetic parameters indicate that K-434Δ deletion mutation does not drastically compromise the enzyme efficiency. The secondary structure and the octameric conformation of both the rSaeno and the K-434Δ mutant are very much stable between pH ranging from 6 to 9, temperatures ranging from 20 to 40 °C and in the presence of divalent metal ions Mg²⁺, Zn²⁺ and Mn²⁺. Under these conditions, the recombinant enzyme and the mutant are also catalytically very active. Intrinsic tryptophan fluorescence (320–380 nm) and CD spectral (195–260 nm) analysis revealed that the secondary structure and the surface architecture of the proteins are not majorly altered by the mutation. But, a significant correlation was observed between the time-dependent decrease in the catalytic activity and the oligomeric stability of rSaeno and K-434Δ mutant. The C-terminal lysine residues in the inter-dimer groove aid in folding and oligomerization of S. aureus enolase.

进行了研究以了解 C 端赖氨酸残基在金黄色葡萄球菌烯醇化酶的催化活性、结构稳定性和寡聚特性中的作用。有趣的是，金黄色葡萄球菌烯醇化酶在溶液中既是稳定的二聚体，又是具有催化活性的易碎八聚体。与六组氨酸标记的金黄色葡萄球菌烯醇化酶 (rSaeno) 相比，缺失突变体的K _m差异可以忽略不计_，但最大反应速度 ( V _max) 和营业额减少 2%。这些动力学参数表明 K-434Δ 缺失突变不会显着影响酶效率。rSaeno 和 K-434Δ 突变体的二级结构和八聚体构象在 pH 范围为 6 到 9、温度范围为 20 到 40 °C 以及存在二价金属离子 Mg ²⁺、Zn的情况下非常稳定²⁺和锰²⁺. 在这些条件下，重组酶和突变体的催化活性也非常高。内在色氨酸荧光（320-380 nm）和 CD 光谱（195-260 nm）分析表明，蛋白质的二级结构和表面结构并未因突变而发生重大变化。但是，在催化活性的时间依赖性降低与 rSaeno 和 K-434Δ 突变体的寡聚稳定性之间观察到显着相关性。二聚体间沟中的 C 端赖氨酸残基有助于金黄色葡萄球菌烯醇化酶的折叠和寡聚化。