赖氨酸-tRNA 合成酶对β-赖氨酸的识别。
β-Lysine discrimination by lysyl-tRNA synthetase.
机构信息
Ohio State Biochemistry Program, Center for RNA Biology, Ohio State University, Columbus, OH 43210, USA.
出版信息
FEBS Lett. 2011 Oct 20;585(20):3284-8. doi: 10.1016/j.febslet.2011.09.008. Epub 2011 Sep 12.
Elongation factor P is modified with (R)-β-lysine by the lysyl-tRNA synthetase (LysRS) paralog PoxA. PoxA specificity is orthogonal to LysRS, despite their high similarity. To investigate α- and β-lysine recognition by LysRS and PoxA, amino acid replacements were made in the LysRS active site guided by the PoxA structure. A233S LysRS behaved as wild type with α-lysine, while the G469A and A233S/G469A variants decreased stable α-lysyl-adenylate formation. A233S LysRS recognized β-lysine better than wildtype, suggesting a role for this residue in discriminating α- and β-amino acids. Both enantiomers of β-lysine were substrates for tRNA aminoacylation by LysRS, which, together with the relaxed specificity of the A233S variant, suggest a possible means to develop systems for in vivo co-translational insertion of β-amino acids.
延伸因子 P 被赖氨酸 tRNA 合成酶 (LysRS) 同工酶 PoxA 修饰为 (R)-β-赖氨酸。尽管 LysRS 和 PoxA 高度相似，但它们的特异性是正交的。为了研究 LysRS 和 PoxA 对 α-和 β-赖氨酸的识别，根据 PoxA 结构对 LysRS 的活性位点进行了氨基酸替换。A233S LysRS 对 α-赖氨酸的行为与野生型相同，而 G469A 和 A233S/G469A 变体则减少了稳定的 α-赖氨酸腺苷酸的形成。A233S LysRS 比野生型更好地识别 β-赖氨酸，表明该残基在区分 α-和 β-氨基酸方面发挥作用。β-赖氨酸的两种对映体都是 LysRS 对 tRNA 氨酰化的底物，这与 A233S 变体的宽松特异性一起，表明可能有办法开发用于体内共翻译插入 β-氨基酸的系统。
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