title: Mass spectrometric characterization of mitochondrial complex I NDUFA10 variants.
abstract: In the present study, we have used a combination of 2-DE and MS to isolate and characterize two variants of the mitochondrial complex I subunit NDUFA10 from Wistar rat brain. Extensive MS/MS analysis revealed that a D/N substitution at position 120 resulting from a 353A/G transition in the coding gene is the biochemical difference between the two most abundant NDUFA10 isoforms. Moreover, 33 modifications of distinct chemical nature targeting 59 specific residues were found to be common to the acidic and basic forms. Positions C67, H149 and H322 of NDUFA10 were specially targeted by different modifications suggesting the high reactivity of these residues and their potential implication in the regulation of the protein function. Together with nonenzymatic modifications that can form in the sample isolation and workup steps, such as oxidation of methionine, tryptophan, cysteine and histidine, we describe amino acid variants of unknown chemical structure that must be further characterized, as well as accumulation of R, K and H methylations and probably K acetylations at the C-terminal region that might play a role in the control of NDUFA10 activity according to similar mechanisms to those described for histones.
authors.affiliation: Division of Hepatology and Gene Therapy, Proteomics Unit and Division of Neurosciences, Center for Applied Medical Research (CIMA), University Hospital of Navarra (CUN), University of Navarra, Pamplona, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Muñoz
authors.forename: Joaquín
authors.initials: J
authors.lastname: Fernández-Irigoyen
authors.forename: Enrique
authors.initials: E
authors.lastname: Santamaría
authors.forename: Axel
authors.initials: A
authors.lastname: Parbel
authors.forename: José
authors.initials: J
authors.lastname: Obeso
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Corrales
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D002853:Chromatography, Liquid / Q000379:methods; D042967:Electron Transport Complex I / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D008928:Mitochondria / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D021122:Protein Subunits; D042967:Electron Transport Complex I