Cytochrome c oxidase in Neurospora crassa contains myristic acid covalently linked to subunit 1.
Radiolabel from [3H]myristic acid was incorporated by Neurospora crassa into the core catalytic subunit 1 of cytochrome c oxidase (EC 1.9.3.1), as indicated by immunoprecipitation. This modification of the subunit, which was specific for myristic acid, represents an uncommon type of myristoylation through an amide linkage at an internal lysine, rather than an N-terminal glycine. The [3H]myristate, which was chemically recovered from the radiolabeled subunit peptide, modified an invariant Lys-324, based upon analyses of proteolysis products. This myristoylated lysine is found within one of the predicted transmembrane helices of subunit 1 and could contribute to the environment of the active site of the enzyme. The myristate was identified by mass spectrometry as a component of mature subunit 1 of a catalytically active, purified enzyme. To our knowledge, fatty acylation of a mitochondrially synthesized inner-membrane protein has not been reported previously.
Vassilev
A O
AO
Department of Plant Biology, University of Minnesota, St. Paul 55108, USA.
Plesofsky-Vig
N
N
Brambl
R
R
D003576:Electron Transport Complex IV / Q000096:biosynthesis* / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D005227:Fatty Acids / Q000032:analysis; D008239:Lysine / Q000031:analogs & derivatives; D008928:Mitochondria / Q000201:enzymology*; D019814:Myristic Acid; D009227:Myristic Acids / Q000032:analysis / Q000378:metabolism*; D009492:Neurospora crassa / Q000201:enzymology*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry; D011233:Precipitin Tests; D011499:Protein Processing, Post-Translational
D005227:Fatty Acids; D009227:Myristic Acids; D010169:Palmitic Acids; D010446:Peptide Fragments; D019814:Myristic Acid; D019308:Palmitic Acid; D003576:Electron Transport Complex IV; D008239:Lysine