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08:57
Aip1p Dynamics Are Altered by the R256H Mutation in Actin
Published on: July 30, 2014
A highly conserved 3-methylhistidine modification is absent in yeast actin
H R Kalhor1, A Niewmierzycka, K F Faull
1Department of Chemistry, University of California, Los Angeles, California, 90095, USA.
Archives of Biochemistry and Biophysics
|September 25, 1999
Summary
Researchers investigated protein histidine methyltransferase in yeast actin, finding histidine-73 is unexpectedly unmodified in Saccharomyces cerevisiae and Candida albicans, unlike rabbit actin. This suggests the methylation evolved later in higher eukaryotes.
Area of Science:
- Biochemistry
- Molecular Biology
- Evolutionary Biology
Background:
- Protein methylation, specifically histidine methylation, is a crucial post-translational modification.
- 3-methylhistidine (3-MeHis) is a conserved residue in actin across many species.
- The presence and function of protein histidine methyltransferases (PHMTs) in yeast are not fully understood.
Purpose of the Study:
- To identify a PHMT in Saccharomyces cerevisiae by examining actin modification.
- To determine if the conserved histidine at position 73 (His-73) in yeast actin is methylated.
- To compare histidine methylation patterns in yeast actin with other eukaryotic actins.
Main Methods:
- Amino acid analysis of purified actin from Saccharomyces cerevisiae and Candida albicans.
- Tryptic digestion of actin followed by amino acid analysis and mass spectrometry.
- Phylogenetic analysis of actin sequences from various eukaryotic organisms.
Main Results:
- Histidine-73 in Saccharomyces cerevisiae actin is not modified with 3-methylhistidine.
- Actin from Candida albicans also lacks modification at His-73.
- Rabbit muscle actin contains the expected 3-methylhistidine residue.
- Phylogenetic analysis indicates 3-MeHis modification in actin evolved after yeast divergence from higher eukaryotes.
Conclusions:
- The identified methodology provides an improved approach for analyzing histidine methylation in proteins.
- The absence of 3-MeHis at His-73 in yeast suggests a loss or late acquisition of this specific methylation event in eukaryotic evolution.
- Further research is needed to identify the specific PHMTs responsible for actin methylation in higher eukaryotes.
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