Thermodynamics of nucleotide binding to NBS-I of the Bacillus subtilis preprotein translocase subunit SecA

被引：23

作者：

den Blaauwen, T ^{[1
]}

van der Wolk, JPW ^{[1
]}

van der Does, C ^{[1
]}

van Wely, KHM ^{[1
]}

Driessen, AJM ^{[1
]}

机构：

[1] Univ Groningen, Dept Microbiol, Groningen Biomol Sci & Biotechnol Inst, NL-9751 NN Haren, Netherlands

来源：

FEBS LETTERS | 1999年 / 458卷 / 02期

关键词：

ATP; differential scanning calorimetry; isothermal titration calorimetry; preprotein translocation; SecA;

D O I：

10.1016/S0014-5793(99)01139-4

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

SecA is the dissociatable nucleotide and preprotein binding subunit of the bacterial translocase, The thermodynamics of nucleotide binding to soluble SecA at nucleotide binding site I were determined by isothermal titration calorimetry. Binding of ADP and non-hydrolyzable ATP gamma S is enthalpy-driven (Delta H-0 of -14.44 and -5.56 kcal/mol, respectively), but is accompanied by opposite entropic contributions (Delta S-0 of -18.25 and 9.55 cal/mol/K, respectively). ADP binding results in a large change in the heat capacity of SecA (Delta C-p = -780 cal/mol/K), It is suggested that ADP binding promotes the interaction between the two thermodynamically discernible domains of SecA which is accompanied by a shielding of hydrophobic surface from solvent. (C) 1999 Federation of European Biochemical Societies.

引用

页码：145 / 150

页数：6

共 31 条

[1] TIGHTLY REGULATED TAC PROMOTER VECTORS USEFUL FOR THE EXPRESSION OF UNFUSED AND FUSED PROTEINS IN ESCHERICHIA-COLI [J].