SOLUTION SECONDARY STRUCTURE OF CALCIUM-SATURATED TROPONIN-C MONOMER DETERMINED BY MULTIDIMENSIONAL HETERONUCLEAR NMR-SPECTROSCOPY

被引：36

作者：

SLUPSKY, CM

REINACH, FC

SMILLIE, LB

SYKES, BD

机构：

[1] UNIV ALBERTA,DEPT BIOCHEM,MRC,PROT STRUCT & FUNCT GRP,EDMONTON,AB T6G 2H7,CANADA

[2] UNIV SAO PAULO,INST QUIM,DEPT BIOQUIM,BR-01498 SAO PAULO,BRAZIL

来源：

PROTEIN SCIENCE | 1995年 / 4卷 / 07期

关键词：

NMR; STRUCTURE; TFE; TROPONIN C;

D O I：

10.1002/pro.5560040704

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：

The solution secondary structure of calcium-saturated skeletal troponin C (TnC) in the presence of 15% (v/v) trifluoroethanol (TFE), which has been shown to exist predominantly as a monomer (Slupsky CM, Kay CM, Reinach FC, Smillie LB, Sykes ED, 1995, Biochemistry 34, forthcoming), has been investigated using multidimensional heteronuclear nuclear magnetic resonance spectroscopy. The H-1, N-15, and C-13 NMR chemical shift values for TnC in the presence of TFE are very similar to values obtained for calcium-saturated NTnC (residues 1-90 of skeletal TnC), calmodulin, and synthetic peptide homodimers. Moreover, the secondary structure elements of TnC are virtually identical to those obtained for calcium-saturated NTnC, calmodulin, and the synthetic peptide homodimers, suggesting that 15% (v/v) TFE minimally perturbs the secondary and tertiary structure of this stably folded protein. Comparison of the solution structure of calcium-saturated TnC with the X-ray crystal Structure of half-saturated TnC reveals differences in the phi/psi angles of residue Glu 41 and in the linker between the two domains. Glu 41 has irregular phi/psi angles in the crystal structure, producing a kink in the B helix, whereas in calcium-saturated TnC, Glu 41 has helical phi/psi angles, resulting in a straight B helix. The linker between the N and C domains of calcium-saturated TnC is flexible in the solution structure.

引用

页码：1279 / 1290

页数：12

共 56 条

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