M. Lipoproteins 3 7 3 3.A.1.127 AmfS Peptide Exporter (AmfS-E) Peptides, Morphogens 2 2 3.A.1.129 CydDC Cysteine Exporter (CydDC-E) Cysteine 1 1 3.A.1.132 Gliding Motility ABC Transporter (Gld) Polysaccharides, Selleck Ipatasertib copper Ions 2 2 3.A.1.134 Peptide-7 Exporter (Pep7E) Peptides, Bacteriocins 3 1 3.A.1.135 Drug Exporter-4 (DrugE4) Drugs 1 2 3.A.1.140 FtsX/FtsE Septation
(FtsX/FtsE) Septation 1 selleckchem 1 3.A.1.141 Ethyl Viologen Exporter (EVE) Ethylviologen 2 2 3.A.1.201 Multidrug Resistance Exporter (MDR) Drugs, Fatty Acids, Lipids 1 2 3.A.1.204 Eye Pigment Precursor Transporter (EPP) Pigments, Drugs, Hemes 2 1 3.A.1.210 Heavy Metal Transporter (HMT) Drugs, Metal Conjugates, Heme 1 1 1 Numbers of integral membrane ABC export proteins in Sco and Mxa arranged by family. ATPases in Sco and Mxa Both Sco and Mxa have a single F-type ATPase as indicated by the 3 integral membrane constituents listed in Additional file 1: Table
S1 and Additional file 2: Table S2. These enzymes function to interconvert chemiosmotic energy (the proton motive force, pmf) with chemical energy (ATP). They both also have an H+-translocating pyrophosphatase complex. P-type ATPases in general appear to function in mediating stress responses in prokaryotes, and their occurrence by family in numerous organismal types has been defined [90, 91]. Sco has eight such enzymes while Mxa has seven. Selleck Necrostatin-1 While only Mxa has a Ca2+-ATPase (Family 2) and only Sco has a heavy metal ATPase (Family 6), both have the three components of Kdp-type K+ uptake ATPases as well as three distinct copper ATPases. Remaining P-type ATPases in these organisms are functionally uncharacterized. Sco has two
members of Family 23 and one member of Family 25 while Mxa has one member each of Families 27 and 32. While Family 23 members are of the type 2 ATPases with 10 TMSs, Families 25, 27 and 32 have the basic type 1 topology of 6 TMSs plus or minus one or two extra N-terminal TMSs . One member of Family 27 has been shown to function in the insertion of copper into copper-dependent oxidases, such as cytochrome oxidase, but not in copper tolerance . This is probably the function of the enzyme in Mxa. Since both organisms have complete Thiamet G cytochrome oxidase systems, it may be that Sco uses an alternative mechanism to insert copper during the biogenesis of this enzyme complex. Possibly, it uses one of its three copper ATPases. Protein secretion As expected, both organisms have the general secretory pathway for protein export (TC# 3.A.5) as well as the Twin arginine targeting (Tat) protein secretion system (TC# 2.A.64) and the DNA translocase (DNA-T). Sco, but not Mxa, appears to have a type IV protein/DNA secretion system (found in both Gram-negative and Gram-positive bacteria). However, only Mxa has components of type II (MTB) and type III protein secretion systems, both present in certain Gram-negative bacteria but lacking in Gram-positive bacteria [93, 94].