title: Ser/Thr/Tyr phosphoproteome characterization of Acinetobacter baumannii: comparison between a reference strain and a highly invasive multidrug-resistant clinical isolate.
abstract: In the current study, the Ser/Thr/Tyr phosphoproteomes of two Acinetobacter baumannii strains, reference (ATCC17978) and highly invasive multidrug-resistant clinical isolate (Abh12O-A2) were analyzed using SCX and TiO2 chromatography followed by high resolution mass spectrometry. We detected a total of 201 unique phosphorylation sites (p-sites), and, after manual validation of peptide spectra, 91 high-confidence phosphorylation events (p-events) could be localized to a specific amino acid residue. The percentage distribution of Ser/Thr/Tyr phosphorylation was 68.9% on serine, 24.1% on threonine and 5.2% on tyrosine in ATCC17978, and 70.8% on serine, 25.2% on threonine and 3.8% on tyrosine in AbH12O-A2. Across all identified p-sites, 11 were identified in ATCC17978 only, while 43 were identified in Abh12O-A2 only, and 37 overlapped between the two strains. Here for the first time we describe the phosphoproteome of A. baumanii, and significance of selected phosphorylation sites is discussed in the context of stress/starvation, pathogenicity and drug resistance.
  
  
  CONCLUSIONS
  It is now well established that protein phosphorylation on Ser/Thr/Tyr residues is an important post-translational modification in bacteria. Herein we employed SCX and TiO2 chromatographic phosphopeptide enrichment combined with LTQ-Orbitrap mass spectrometric analyses to characterize and establish a qualitative comparison between the Ser/Thr/Tyr phosphoproteomes of two Acinetobacter baumannii strains: a reference strain and a highly invasive multidrug-resistant clinical isolate. We highlight the identification of phosphoproteins with a role in pathogenicity and those involved in drug resistance.
authors.affiliation: Proteome Center Tuebingen, University of Tuebingen, Germany; Laboratorio de Microbiología, Instituto de Investigación Biomedica de A Coruña (INIBIC), Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña (CHUAC), Spain; Division of Medical Biochemistry (Dep. of Clinical Laboratory Sciences), Institute of Infectious Disease and Molecular Medicine, University of Cape Town-Medical School, Anzio, Observatory, Cape Town 7925, South Africa. Electronic address: nelsonasoares@gmail.com.
authors.forename: Nelson C
authors.initials: NC
authors.lastname: Soares
authors.affiliation: Proteome Center Tuebingen, University of Tuebingen, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Spät
authors.affiliation: Laboratorio de Microbiología, Instituto de Investigación Biomedica de A Coruña (INIBIC), Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña (CHUAC), Spain.
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Méndez
authors.affiliation: Division of Medical Biochemistry (Dep. of Clinical Laboratory Sciences), Institute of Infectious Disease and Molecular Medicine, University of Cape Town-Medical School, Anzio, Observatory, Cape Town 7925, South Africa.
authors.forename: Kehilwe
authors.initials: K
authors.lastname: Nakedi
authors.affiliation: Laboratorio de Microbiología, Instituto de Investigación Biomedica de A Coruña (INIBIC), Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña (CHUAC), Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Aranda
authors.affiliation: Laboratorio de Microbiología, Instituto de Investigación Biomedica de A Coruña (INIBIC), Servicio de Microbiología, Complejo Hospitalario Universitario A Coruña (CHUAC), Spain. Electronic address: German.Bou.Arevalo@sergas.es.
authors.forename: German
authors.initials: G
authors.lastname: Bou
mesh_terms: D040981:Acinetobacter baumannii / Q000378:metabolism*; D000595:Amino Acid Sequence; D002845:Chromatography; D024901:Drug Resistance, Multiple, Bacterial; D006019:Glycolysis; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010641:Phenotype; D010766:Phosphorylation; D020543:Proteome / Q000378:metabolism; D040901:Proteomics; D012694:Serine / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D013912:Threonine / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D010455:Peptides; D020543:Proteome; C009495:titanium dioxide; D013912:Threonine; D014443:Tyrosine; D012694:Serine; D014025:Titanium
keywords: Acinetobacter baumannii; ORBITRAP; Phosphoproteome; Phosphoproteomics