What question did this study set out to answer?

To investigate the transient kinetic effects of replacing three conserved glycine residues (G680, G684, and G691) with alanine in the reactive thiol region of Dictyostelium discoideum myosin II.

April 20, 1999Biochemistry

Kinetic Analysis of Dictyostelium discoideum Myosin Motor Domains with Glycine-to-Alanine Mutations in the Reactive Thiol Region

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Population

Dictyostelium discoideum myosin II soluble myosin head fragment M761-2R

Comparison

Glycine-to-alanine mutations in the reactive… vs Unmutated M761-2R

Design

Preclinical

Authors

RBRenu BatraForschungszentrum Jülich MGMichael A. GeevesHeart Failure / Cardiomyopathy DMDietmar J. MansteinMedizinische Hochschule Hannover

Discussion

Member takes

Implication

Highlights critical residues for myosin nucleotide kinetics; extends biochemical models but leaves open relevance to cardiac myosins.

Key Points

To investigate the transient kinetic effects of replacing three conserved glycine residues (G680, G684, and G691) with alanine in the reactive thiol region of Dictyostelium discoideum myosin II.
Engineered G680A, G684A, and G691A point mutations into the soluble Dictyostelium myosin head fragment M761-2R.
Characterized basal and actin-stimulated ATP turnover, cleavage steps, and nucleotide binding affinities using transient kinetic methods and fluorescent mantADP.
G680A exhibited 20- to 30-fold slower nucleotide binding rates, an approximately 10-fold higher affinity for mantADP driven by a 200-fold reduction in its dissociation rate, and thermodynamic uncoupling of actin and ADP binding.
G684A and G691A demonstrated a 4-fold reduction in the ATP cleavage rate compared to M761-2R.
G691A displayed increased basal Mg2+-ATPase activity with facilitated phosphate release, but actin addition stimulated ATP turnover by no more than 3-fold.

Structured PICO

Population

Dictyostelium discoideum myosin II soluble myosin head fragment M761-2R

Intervention

Glycine-to-alanine mutations (G680A, G684A, and G691A) in the reactive thiol region

Comparator

Unmutated M761-2R

Outcome

Kinetic properties including Mg2+-ATPase activity, ATP cleavage rate, and nucleotide bindingsurrogate

Glycine-to-alanine mutations in the reactive thiol region of Dictyostelium discoideum myosin II significantly alter its kinetic properties, particularly nucleotide binding and ATP cleavage.

Cite This Study

Batra et al. (1999) studied this question.

synapsesocial.com/papers/6a95c08375656758994f09ce https://doi.org/10.1021/bi982251e

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Kinetic Analysis of Dictyostelium discoideum Myosin Motor Domains with Glycine-to-Alanine Mutations in the Reactive Thiol Region

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Kinetic Analysis of Dictyostelium discoideum Myosin Motor Domains with Glycine-to-Alanine Mutations in the Reactive Thiol Region

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

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