Experimental investigation of the seesaw mechanism of the relay region that moves the myosin lever arm

Bálint Kintses, Zhenhui Yang, A. Málnási-Csizmadia

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A seesaw-like movement of the relay region upon the recovery step of myosin was recently simulated in silico. In this model the relay helix tilts around its pivoting point formed by a phenylalanine cluster (Phe481, Phe482, and Phe652), which moves the lever arm of myosin. To study the effect of the elimination of the proposed pivoting point, these phenylalanines were mutated to alanines in two Dictyostelium myosin II motor domain constructs (MF481A, F482A and MF652A). The relay movement was followed by the fluorescence change of Trp501 located in the relay region. The steady-state and transient kinetic fluorescence experiments showed that the lack of the phenylalanine fulcrum perturbs the formation of the "up" lever arm state, and only moderate effects were found in the nucleotide binding, the formation of the "down" lever arm position, and the ATP hydrolysis steps. We conclude that the lack of the fulcrum decouples the distal part of the relay from the nucleotide binding site upon the recovery step. Our molecular dynamics simulations also showed that the conformation of the motor is not perturbed by the mutation in the down lever arm state, however, the lack of the pivoting point rearranges the dynamic pattern of the kink region of the relay helix.

Original languageEnglish
Pages (from-to)34121-34128
Number of pages8
JournalJournal of Biological Chemistry
Volume283
Issue number49
DOIs
Publication statusPublished - Dec 5 2008

Fingerprint

Myosins
Phenylalanine
Nucleotides
Fluorescence
Myosin Type II
Recovery
Dictyostelium
Molecular Dynamics Simulation
Alanine
Computer Simulation
Conformations
Molecular dynamics
Hydrolysis
Adenosine Triphosphate
Binding Sites
Mutation
Kinetics
Computer simulation
Experiments

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Molecular Biology

Cite this

Experimental investigation of the seesaw mechanism of the relay region that moves the myosin lever arm. / Kintses, Bálint; Yang, Zhenhui; Málnási-Csizmadia, A.

In: Journal of Biological Chemistry, Vol. 283, No. 49, 05.12.2008, p. 34121-34128.

Research output: Contribution to journalArticle

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