Archaeal N-terminal protein maturation commonly involves N-terminal acetylation: a large-scale proteomics survey.
We present the first large-scale survey of N-terminal protein maturation in archaea based on 873 proteomically identified N-terminal peptides from the two haloarchaea Halobacterium salinarum and Natronomonas pharaonis. The observed protein maturation pattern can be attributed to the combined action of methionine aminopeptidase and N-terminal acetyltransferase and applies to cytosolic proteins as well as to a large fraction of integral membrane proteins. Both N-terminal maturation processes primarily depend on the amino acid in penultimate position, in which serine and threonine residues are over represented. Removal of the initiator methionine occurs in two-thirds of the haloarchaeal proteins and requires a small penultimate residue, indicating that methionine aminopeptidase specificity is conserved across all domains of life. While N-terminal acetylation is rare in bacteria, our proteomic data show that acetylated N termini are common in archaea affecting about 15% of the proteins and revealing a distinct archaeal N-terminal acetylation pattern. Haloarchaeal N-terminal acetyltransferase reveals narrow substrate specificity, which is limited to cleaved N termini starting with serine or alanine residues. A comparative analysis of 140 ortholog pairs with identified N-terminal peptide showed that acetylatable N-terminal residues are predominantly conserved amongst the two haloarchaea. Only few exceptions from the general N-terminal acetylation pattern were observed, which probably represent protein-specific modifications as they were confirmed by ortholog comparison.
Falb
Michaela
M
Department of Membrane Biochemistry, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany.
Aivaliotis
Michalis
M
Garcia-Rizo
Carolina
C
Bisle
Birgit
B
Tebbe
Andreas
A
Klein
Christian
C
Konstantinidis
Kosta
K
Siedler
Frank
F
Pfeiffer
Friedhelm
F
Oesterhelt
Dieter
D
D000107:Acetylation; D000409:Alanine / Q000378:metabolism; D000595:Amino Acid Sequence; D000626:Aminopeptidases / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017124:Conserved Sequence; D019617:Halobacterium salinarum / Q000201:enzymology; D013058:Mass Spectrometry; D063208:Methionyl Aminopeptidases; D008954:Models, Biological; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D040901:Proteomics; D012694:Serine / Q000378:metabolism; D013379:Substrate Specificity
D019843:Archaeal Proteins; D010446:Peptide Fragments; D012694:Serine; D000626:Aminopeptidases; D063208:Methionyl Aminopeptidases; D000409:Alanine