Table 1

Functional categorization of OM and periplasmic proteins statistically significantly over- and underrepresented in SOMVs

Functional category and protein name or NMB designationFunctionFold SOMV/OM changeaRelative amt in SOMVsb
OM proteins overrepresented
    Autotransporter proteins
        AppAdhesion and penetration protein4.72213.33
        AusIAutotransporter, serine-type peptidase4.10116.33
        NalPAutotransporter protease3.1019
        IgaIgA-specific serine endopeptidase2.71278
        NadAPutative adhesin/invasin2.0419
    Complement regulatory proteins
        fHbpFactor H-binding protein3.7884
        OpcClass 5 OM protein3.162,132
        NspAOM protein3.1036.67
        NhbAHeparin-binding protein A2.325.67
    Two-partner secretion proteins
        HprATPSS,c secreted component2.716
        HprBTPSS, transporter protein1.9416.67
    Tr metal (iron, zinc, others) binding and uptake proteins
        Tbp2Transferrin-binding protein 23.8010.67
        Tbp1Transferrin-binding protein 11.99130.33
        LbpALactoferrin-binding protein A1.785
        HpuBHemoglobin receptor1.3836
        ZnuDZinc uptake component D1.66220.33
        FetAIron-regulated OM protein FrpB1.5617.67
        FetBIron(III) ABC transporter, periplasmic binding protein1.064
        NMB1829TonB-dependent receptor1.327.33
    Autolysin OMPLAOM phospholipase A1.4930.67
    Unknown function
        NMB1578Conserved hypothetical protein1.96
        NMB2139Conserved hypothetical protein1.797.67
        NMB0035Conserved hypothetical protein1.1325.67
        NMB2134Conserved hypothetical protein1.0613.67
        NMB1212Hypothetical protein1.852.33
        NMB0841Hypothetical protein1.685
        NMB1084Hypothetical protein1.6343.67
        NMB1035Hypothetical protein1.4622.67
        NMB1213Putative lipoprotein1.7414.33
        NMB0204Putative lipoprotein1.7317
        NMB0873Putative OM protein1.6310.67
        NMB2091Putative hemolysin1.5840.67
        NMB0707Putative rare lipoprotein B1.5320.67
        NMB1898Lipoprotein1.4021.67
    Other transporters
        PotD-3Spermidine/putrescine ABC transporter2.065.67
        PotD-1Spermidine/putrescine ABC transporter1.6134
        NMB0787Amino acid ABC transporter1.2346
        NMB0623Spermidine/putrescine ABC transporter1.1822.67
OM proteins underrepresented
    Porins
        PorAMajor OM protein PorA0.70621.33
        PorBMajor OM protein PorB0.691,604
    Membrane integrity protein RmpMOM protein class 40.5846.67
    Drug efflux protein MtrEMultidrug efflux pump channel protein0.3122
    Pilus-related protein PilQPilus pore protein PilQ0.4469
    Other
        MipMacrophage infectivity potentiator0.7724.33
    Unknown function
        NMB0086Hypothetical protein0.922.67
        NMB1369Hypothetical protein0.822.33
        NMB1592Putative lipoprotein0.817.67
Periplasmic proteins overrepresented
    Transporter proteins
        NMB0041ABC transporter, periplasmic solute binding protein3.4317
        FbpAIron(III) ABC transporter, periplasmic binding protein3.2774.33
        ZnuAZinc uptake component A2.0514
        NMB1017Sulfate ABC transporter, periplasmic sulfate-binding protein1.2022.67
    Functional maturation of proteins
        DsbCThiol-disulfite interchange protein3.4110.67
        NMB0006Thioredoxin-related protein3.055.67
        DsbA3Thiol-disulfite interchange protein2.852
    Unknown function
        NMB1030Conserved hypothetical protein3.4417
        NMB1963Conserved hypothetical protein3.3911.67
        NMB0355Conserved hypothetical protein3.358.33
        NMB0783Conserved hypothetical protein3.335.33
        NMB0345Putative cell-binding factor3.2752.67
        NMB1475Conserved hypothetical protein3.1355.33
        NMB2074Hypothetical protein1.8511.67
        NMB1557Conserved hypothetical protein1.832
        NMB0088Putative OM protein P11.5157.33
        NMB0872Conserved hypothetical protein1.285.67
        NMB0313Conserved hypothetical protein1.2625.33
    Cell wall biogenesis protein NMB1620Putative muramoyltetrapeptide carboxypeptidase1.353
Periplasmic proteins underrepresented
    Cell wall remodeling
        MltAMembrane-bound lytic murein transglycosylase A0.896
        MltBMembrane-bound lytic murein transglycosylase B0.750
        SltPutative soluble lytic murein transglycosylase0.7522.33
    Functional maturation of proteins
        DsbA1Thiol-disulfite interchange protein0.813.33
        DsbA2Thiol-disulfite interchange protein0.7814
    Membrane integrity protein NMB0109Putative PG-binding periplasmic protein0.7927
  • a Ratio of relative SOMV and OM protein abundances obtained by MS quantification against the metabolically labeled internal standard.

  • b Relative amount of protein within the SOMV fraction based on NSAFs. Statistical significance was calculated with Student's t test. P < 0.05 was defined as statistically significant.

  • c TPSS, two-partner secretion system.