Conformational stabilities of the structural repeats of erythroid spectrin and their functional implications

被引:58
作者
An, XL
Guo, XH
Zhang, XH
Baines, AJ
Debnath, G
Moyo, D
Salomao, M
Bhasin, N
Johnson, C
Discher, D
Gratzer, WB
Mohandas, N
机构
[1] New York Blood Ctr, Red Cell Physiol Lab, New York, NY 10021 USA
[2] Univ Kent, Dept Biosci, Canterbury CT2 7NJ, Kent, England
[3] Kings Coll London, Randall Ctr Mol Mech Cell Funct, London SE1 1UL, England
[4] Univ Penn, Biophys Engn Lab, Philadelphia, PA 19104 USA
关键词
D O I
10.1074/jbc.M513725200
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 two polypeptide chains of the erythroid spectrin heterodimer contain between them 36 structural repeating modules, which can function as independently folding units. We have expressed all 36 and determined their thermal stabilities. These vary widely, with unfolding transition mid-points (T-m) ranging from 21 to 72 C. Eight of the isolated repeats are largely unfolded at physiological temperature. Constructs comprising two or more adjacent repeats show inter-repeat coupling with coupling free energies of several kcal mol(-1). Constructs comprising five successive repeats from the beta-chain displayed cooperativity and strong temperature dependence in forced unfolding by atomic force microscopy. Analysis of aligned sequences and molecular modeling suggests that high stability is conferred by large hydrophobic side chains at position e of the heptad hydrophobic repeats in the first helix of the three-helix bundle that makes up each repeat. This inference was borne out by the properties of mutants in which the critical residues have been replaced. The marginal stability of the tertiary structure at several points in the spectrin chains is moderated by energetic coupling with adjoining structural elements but may be expected to permit adaptation of the membrane to the large distortions that the red cell experiences in the circulation.
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页码:10527 / 10532
页数:6
相关论文
共 34 条
[1]   Phosphatidylserine binding sites in erythroid spectrin: Location and implications for membrane stability [J].
An, XL ;
Guo, XH ;
Sum, H ;
Morrow, J ;
Gratzer, W ;
Mohandas, N .
BIOCHEMISTRY, 2004, 43 (02) :310-315
[2]  
Baines AJ, 2003, CELL MOL BIOL LETT, V8, P195
[3]   Cooperative folding in a multi-domain protein [J].
Batey, S ;
Randles, LG ;
Steward, A ;
Clarke, J .
JOURNAL OF MOLECULAR BIOLOGY, 2005, 349 (05) :1045-1059
[4]   PROTEIN STABILITY CURVES [J].
BECKTEL, WJ ;
SCHELLMAN, JA .
BIOPOLYMERS, 1987, 26 (11) :1859-1877
[5]  
BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248, DOI 10.1016/0003-2697(76)90527-3
[6]   CALORIMETRIC STUDIES OF STRUCTURAL TRANSITIONS OF HUMAN ERYTHROCYTE-MEMBRANE - INVOLVEMENT OF SPECTRIN IN A-TRANSITION [J].
BRANDTS, JF ;
ERICKSON, L ;
LYSKO, K ;
SCHWARTZ, AT ;
TAVERNA, RD .
BIOCHEMISTRY, 1977, 16 (15) :3450-3454
[7]  
DAVIS J, 1983, J BIOL CHEM, V258, P7757
[8]  
Discher DE, 2001, CELL MOL BIOL LETT, V6, P593
[9]   Structure of the α-actinin rod:: Molecular basis for cross-linking of actin filaments [J].
Djinovic-Carugo, K ;
Young, P ;
Gautel, M ;
Saraste, M .
CELL, 1999, 98 (04) :537-546
[10]   Knowledge-based protein secondary structure assignment [J].
Frishman, D ;
Argos, P .
PROTEINS-STRUCTURE FUNCTION AND GENETICS, 1995, 23 (04) :566-579