TABLE 1.
Gene products of the extracellular polysaccharide biosynthesis gene cluster of Aquincola tertiaricarbonis strain RN12 and the predicted orthologues in the closely related proteobacterial genomes of Rubrivivax gelatinosus IL-144 and Leptothrix cholodnii SP-6
| A. tertiaricarbonis RN12 proteina | Predicted functionb | Polypeptide sequence identity (%) betwen RN12 andc: |
|
|---|---|---|---|
| Rubrivivax gelatinosus IL-144 | Leptothrix cholodnii SP-6 | ||
| Wza | EPS export | 82 | 62 |
| Wzz | EPS chain length determinant | 60 | 39 |
| Tyrosine kinase Wzc | EPS chain length determinant | 69 | 52 |
| Porin β-barrel | Glycine-rich outer membrane porin for EPS export | 32 | 27 |
| Secretion ATPase | Putative secretion ATPase | 72 | 53 |
| Polysaccharide deacetylase | Removal of acetyl group from EPS | 78 | — |
| FemAB-like protein | EPS modification | 70 | — |
| Glycosyltransferase 1 | EPS unit biosynthesis | 63 | — |
| EpsH | Exosortase A | 46 | 27 |
| Glycosyltransferase 2 | EPS unit biosynthesis | 51 | 32 |
| GtrA family protein | Unknown | 30 | — |
| Glycosyltransferase 3 | EPS unit biosynthesis | — | — |
| Hypothetical protein | Unknown | — | — |
| AsnH | Asparagine synthesis | 71 | 37 |
| GDP-mannose 6-dehydrogenase AlgD | Production of GDP-mannuronate | 35 | — |
| Glycosyltransferase 4 | EPS unit biosynthesis | — | — |
| Glycosyltransferase 5 | EPS unit biosynthesis | 39 | — |
| Wzy polymerase | EPS polymerase | 45 | — |
| Polysaccharide deacetylase | Removal of acetyl group from EPS | 36 | 28 |
| Beta-1,4-GalT | Beta-1,4-galactosyltransferase for EPS unit biosynthesis | — | — |
| SAM-dependent methyltransferase | SAM-dependent methylation of EPS? | — | — |
| WzxC flippase | Flipping (export) of EPS units | — | — |
| Hypothetical protein | Unknown | — | — |
| Glycosyltransferase 6 | EPS unit biosynthesis | 37 | 31 |
| AsnB | Asparagine synthesis | 61 | — |
| NosD-like protein | Enzyme maturation protein | 52 | — |
| Hypothetical protein | Acetyltransferase (GNAT) for EPS acetylation? | 23 | |
| Sugar aminotransferase WecE | Production of TDP-4-amino-4,6- dideoxy-d-galactose | — | — |
| TPR protein | Protein scaffold for EPS synthesis | — | — |
| Alpha/beta-hydrolase superfamily esterase 1 | Modification of EPS? | — | — |
| Alpha/beta-hydrolase superfamily esterase 2 | Modification of EPS? | 58 | — |
| Acyl carrier protein AcpP | Lipid and fatty acid metabolism | 30 | 29 |
| Acyl-CoA synthetase and ligase | AMP-dependent synthesis of acyl-CoA | 30 | — |
| UDP-glucuronate 4-epimerase Uge | Synthesis of UDP-d-galacturonate | 73 | 67 |
| UDP-glucose 6-dehydrogenase Ugd | Synthesis of UDP-glucuronate | 78 | 74 |
| Diaminopimelate decarboxylase | Unknown | — | — |
a
Proteins shown in boldface are encoded by those genes disrupted by a transposon insertion. SAM, S-adenosyl methionine; TPR, tetratricopeptide repeat; CoA, coenzyme A.
b
EPS, exopolysaccharide.
c
The NCBI accession number of the reference EPS biosynthesis gene cluster of Aquincola tertiaricarbonis RN12 strain is KY053276. —, no orthologue was found.