Actin-induced closure of the actin-binding cleft of smooth muscle myosin

Christopher M. Yengo, Enrique M. De La Cruz, Lynn R. Chrin, Donald P. Gaffney, Christopher L. Berger

Research output: Contribution to journalArticle

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Abstract

The putative actin-binding interface of myosin is separated by a large cleft that extends into the base of the nucleotide binding pocket, suggesting that it may be important for mediating the nucleotide-dependent changes in the affinity for myosin on actin. We have genetically engineered a truncated version of smooth muscle myosin containing the motor domain and the essential light chain-binding region (MDE), with a single tryptophan residue at position 425 (F425W-MDE) in the actin-binding cleft. Steady-state fluorescence of F425W-MDE demonstrates that Trp-425 is in a more solvent-exposed conformation in the presence of MgATP than in the presence of MgADP or absence of nucleotide, consistent with closure of the actin-binding cleft in the strongly bound states of MgATPase cycle for myosin. Transient kinetic experiments demonstrate a direct correlation between the rates of strong actin binding and the conformation of Trp-425 in the actin-binding cleft, and suggest the existence of a novel conformation of myosin not previously seen in solution or by x-ray crystallography. Thus, these results directly demonstrate that: 1) the conformation of the actin-binding cleft mediates the affinity of myosin for actin in a nucleotide-dependent manner, and 2) actin induces conformational changes in myosin required to generate force and motion during muscle contraction.

Original languageEnglish (US)
Pages (from-to)24114-24119
Number of pages6
JournalJournal of Biological Chemistry
Volume277
Issue number27
DOIs
StatePublished - Jul 5 2002

Fingerprint

Smooth Muscle Myosins
Actins
Myosins
Conformations
Nucleotides
Crystallography
Muscle Contraction
Tryptophan
Adenosine Diphosphate
Muscle
Adenosine Triphosphate
Fluorescence
X-Rays
Light
X rays

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Yengo, Christopher M. ; De La Cruz, Enrique M. ; Chrin, Lynn R. ; Gaffney, Donald P. ; Berger, Christopher L. / Actin-induced closure of the actin-binding cleft of smooth muscle myosin. In: Journal of Biological Chemistry. 2002 ; Vol. 277, No. 27. pp. 24114-24119.
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Yengo, CM, De La Cruz, EM, Chrin, LR, Gaffney, DP & Berger, CL 2002, 'Actin-induced closure of the actin-binding cleft of smooth muscle myosin', Journal of Biological Chemistry, vol. 277, no. 27, pp. 24114-24119. https://doi.org/10.1074/jbc.M111253200

Actin-induced closure of the actin-binding cleft of smooth muscle myosin. / Yengo, Christopher M.; De La Cruz, Enrique M.; Chrin, Lynn R.; Gaffney, Donald P.; Berger, Christopher L.

In: Journal of Biological Chemistry, Vol. 277, No. 27, 05.07.2002, p. 24114-24119.

Research output: Contribution to journalArticle

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AU - Yengo, Christopher M.

AU - De La Cruz, Enrique M.

AU - Chrin, Lynn R.

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AU - Berger, Christopher L.

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