核糖核酸酶T1折叠过程中肽基脯氨酰顺反异构化的抗体催化作用。
Antibody catalysis of peptidyl-prolyl cis-trans isomerization in the folding of RNase T1.
作者信息
Ma L, Hsieh-Wilson L C, Schultz P G
机构信息
Howard Hughes Medical Institute, Department of Chemistry, University of California, Berkeley, CA 94720, USA.
出版信息
Proc Natl Acad Sci U S A. 1998 Jun 23;95(13):7251-6. doi: 10.1073/pnas.95.13.7251.
An antibody generated to an alpha-keto amide containing hapten 1 catalyzes the cis-trans isomerization of peptidyl-prolyl amide bonds in peptides and in the protein RNase T1. The antibody-catalyzed peptide isomerization reaction showed saturation kinetics for the cis-substrate, Suc-Ala-Ala-Pro-Phe-pNA, with a kcat/Km value of 883 s-1.M-1; the reaction was inhibited by the hapten analog 13 (Ki = 3. 0 +/- 0.4 microM). Refolding of denatured RNase T1 to its native conformation also was catalyzed by the antibody, with the antibody-catalyzed folding reaction inhibitable both by the hapten 1 and hapten analog 13. These results demonstrate that antibodies can catalyze conformational changes in protein structure, a transformation involved in many cellular processes.
针对含半抗原1的α-酮酰胺产生的抗体，可催化肽以及蛋白质核糖核酸酶T1中肽基 - 脯氨酰胺键的顺反异构化。抗体催化的肽异构化反应对顺式底物琥珀酰 - 丙氨酰 - 丙氨酰 - 脯氨酰 - 苯丙氨酰 - 对硝基苯胺（Suc - Ala - Ala - Pro - Phe - pNA）呈现饱和动力学，催化常数与米氏常数的比值（kcat/Km）为883 s-1·M-1；该反应被半抗原类似物13抑制（抑制常数Ki = 3.0±0.4微摩尔）。变性的核糖核酸酶T1重折叠为其天然构象的过程也由该抗体催化，抗体催化的折叠反应可被半抗原1和半抗原类似物13抑制。这些结果表明，抗体能够催化蛋白质结构的构象变化——这是一个涉及许多细胞过程的转变。
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