A novel 3-methylhistidine modification of yeast ribosomal protein Rpl3 is dependent upon the YIL110W methyltransferase.
We have shown that Rpl3, a protein of the large ribosomal subunit from baker's yeast (Saccharomyces cerevisiae), is stoichiometrically monomethylated at position 243, producing a 3-methylhistidine residue. This conclusion is supported by top-down and bottom-up mass spectrometry of Rpl3, as well as by biochemical analysis of Rpl3 radiolabeled in vivo with S-adenosyl-l-[methyl-(3)H]methionine. The results show that a +14-Da modification occurs within the GTKKLPRKTHRGLRKVAC sequence of Rpl3. Using high-resolution cation-exchange chromatography and thin layer chromatography, we demonstrate that neither lysine nor arginine residues are methylated and that a 3-methylhistidine residue is present. Analysis of 37 deletion strains of known and putative methyltransferases revealed that only the deletion of the YIL110W gene, encoding a seven β-strand methyltransferase, results in the loss of the +14-Da modification of Rpl3. We suggest that YIL110W encodes a protein histidine methyltransferase responsible for the modification of Rpl3 and potentially other yeast proteins, and now designate it Hpm1 (Histidine protein methyltransferase 1). Deletion of the YIL110W/HPM1 gene results in numerous phenotypes including some that may result from abnormal interactions between Rpl3 and the 25 S ribosomal RNA. This is the first report of a methylated histidine residue in yeast cells, and the first example of a gene required for protein histidine methylation in nature.
Webb
Kristofor J
KJ
Department of Chemistry and Biochemistry and the Molecular Biology Institute, University of California Los Angeles, Los Angeles, California 90095-1569, USA.
Zurita-Lopez
Cecilia I
CI
Al-Hadid
Qais
Q
Laganowsky
Arthur
A
Young
Brian D
BD
Lipson
Rebecca S
RS
Souda
Puneet
P
Faull
Kym F
KF
Whitelegge
Julian P
JP
Clarke
Steven G
SG
D000595:Amino Acid Sequence; D008762:Methylhistidines / Q000378:metabolism*; D008780:Methyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D012269:Ribosomal Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D008762:Methylhistidines; D012269:Ribosomal Proteins; C521718:Rpl3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C000609573:Hpm1 protein, S cerevisiae; D008780:Methyltransferases; C028118:3-methylhistidine