Modular Motif, Structural Folds and Affinity Profiles of the PEVK Segment of Human Fetal Skeletal Muscle Titin

Gustavo Gutierrez-Cruz, Ann H. Van Heerden, Kuan Wang

研究成果: 雜誌貢獻文章同行評審

74 引文 斯高帕斯(Scopus)

摘要

The extension of the PEVK segment of the giant elastic protein titin is a key event in the elastic response of striated muscle to passive stretch. PEVK behaves mechanically as an entropic spring and is thought to be a random coil. cDNA sequencing of human fetal skeletal PEVK reveals a modular motif with tandem repeats of modules averaging 28 residues and with superrepeats of seven modules. Conformational studies of bacterially expressed 53-kDa fragment (TP1) by circular dichroism suggest that this soluble protein contains substantial polyproline II (PPII) type left-handed helices. Urea and thermal titrations cause gradual and reversible decrease in PPII content. The absence of sharp melting in urea and thermal titrations suggests that there is no long range cooperativity among the PPII helices. Studies with solid phase and surface plasmon resonance assays indicate that TP1 interacts with actin and some but not all cloned nebulin fragments with high affinity. Interestingly, Ca 2+/calmodulin and Ca2+/S100 abolish nebulin/PEVK interaction. We suggest that in aqueous solution, PEVK is an open and flexible chain of relatively stable structural folds of the polyproline II type. PEVK region of titin may be involved in interfilament association with thin filaments in a calcium/calmodulin sensitive manner. This adhesion may modulate titin extensibility and elasticity.

原文英語
頁(從 - 到)7442-7449
頁數8
期刊Journal of Biological Chemistry
276
發行號10
DOIs
出版狀態已發佈 - 三月 9 2001
對外發佈Yes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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