EC Number   |
General Information |
Reference |
|---|
   2.3.2.17 | malfunction |
a femA deletion leads to accumulation of monoglycine which decreases the interpeptide cross-linking in the peptidoglycan (PGN) sacculus as compared to wild-type cells |
760162 |
| 2.3.2.17 | malfunction |
decreased expression of the femA gene leads to reduced methicillin resistance |
719675 |
| 2.3.2.17 | metabolism |
all investigated strains, either methicillin-resistant or susceptible, express FemA during the exponential growth phase in varying amounts. In the stationary phase, the FemA content is diminished. Strains in which FemA is inactivated by insertion of Tn551 into the control region of the FemAB operon still express about 10% of the protein compared to their parent strains. Tn551 insertion in the middle of the femB gene does not affect the FemA expression |
703743 |
| 2.3.2.17 | metabolism |
kinase Stk and phosphatase Stp modulate cell wall synthesis and cell division at several levels. Enzyme FemA interacts with the eukaryotic-like serine/threonine kinase Stk, but is not phosphorylated by it, while the lipid II:glycine glycyltransferase FemX can be phosphorylated by the Ser/Thr kinase Stk in vitro. The cognate phosphatase Stp dephosphorylates these phosphorylation sites. Stk interacts with FemA/B and other cell wall synthesis and cell division proteins, but Stk does not phosphorylate FemA and FemB. Interaction network of Stk, Stp and FemX/A/B proteins among cell wall synthesis and cell division proteins as determined by bacterial two-hybrid analysis, overview |
760162 |
| 2.3.2.17 | physiological function |
expression levels of femA in methicillin-sensitive, low-level methicillin-resistant and high-level methicillin-resistant Staphylococcus aureus are 0.035%-29.91%, 0.055%-310% and 13.88-5500%, respectively. EMSA detects a signal shift in 57 high-level methicillin-resistant isolates but not in four low-level methicillin-resistant and four methicillin-sensitive strains. Expression of femA in high-level methicillin-resistant non-beta-lactamase-producing strains is higher than in low-level methicilln-resistant and methicillin-sensitive strains |
704984 |
| 2.3.2.17 | physiological function |
FemA catalyzes the second step in the synthesis of the pentaglycine interpeptide bridge crosslinking different glycan strands in Staphylococcus aureus. FemX adds the first glycine residue to MurNAc-L-Ala-D-Glu-(N6-Gly)L-Lys-D-Ala-D-Ala-diphosphoundecaprenyl-M-acetylglucosamine, i.e. lipid II. Addition of glycine residues 2, 3 and glycine residues 4, 5 is catalyzed by enzymes FemA and FemB, respectively. None of the FemABX enzymes requires the presence of one or two of the other Fem proteins for activity, rather, bridge formation is delayed in an in vitro system when all 3 enzymes are present |
705764 |
| 2.3.2.17 | physiological function |
FemA is needed for cell growth in the presence of beta-lactam antibiotics, it has no influence on the synthesis of the low affinity, additional penicillin-binding protein PBP2' encoded by mec and known to be essential for cell wall synthesis in the presence of inhibitory concentrations of methicillin |
705741 |
| 2.3.2.17 | physiological function |
femA mutants leading to truncated proteins still produce intact FemB while exhibiting a phenotype identical to femAB double mutants, such as same muropeptide pattern. FemA is essential for the addition of glycine residues 2 and 3 only to the staphylococcal interpeptide bridge |
704256 |
| 2.3.2.17 | physiological function |
surface protein is linked to tri- and monoglycyl cross-bridges of peptidoglycan isolated from femB and femA mutant staphylococci, respectively. No surface protein is found linked directly to the epsilon-amino group of lysyl within the cell wall of a femAX strain. Peptidoglycan analysis of a femAB mutant strain reveals the presence of pentaglycyl, tetraglycyl-monoseryl, and monoglycyl as well as small amounts of triglycyl cross-bridges. Analysis of anchor peptides shows that surface proteins are mostly linked to tetraglycylmonoseryl as well as pentaglycyl. The sortase activity of Staphylococcus aureus prefers cross-bridges containing five residues, but altered cell-wall cross-bridges can be linked to the COOH-terminal end of surface proteins |
704390 |
| 2.3.2.17 | physiological function |
the bacterial cell envelope is essential for survival and pathogenicity. It forms a barrier against environmental stresses and contributes to virulence and antibiotic resistance. The cell wall of Gram-positive bacteria is composed of a multi-layered mesh of cross-linked peptidoglycan (PGN). PGN consists of chains of repeating disaccharide units comprising N-acetylglucosamine (GlcNAc) and N-acetylmuramic acid (MurNAc). The lactoyl group of MurNAc is supplemented with a penta stem peptide (L-Ala-D-isoGlu-L-Lys-D-Ala-D-Ala). The staphylococcal PGN polysaccharide chains are highly cross-linked via interpeptide bridges of five glycyl residues protruding from the L-lysine of the stem-peptides4. These interpeptide bridges are synthesized by the FemX/A/B enzymes. These non-ribosomal peptidyl-transferases use glycyltRNAs to sequentially add five glycine's to the PGN-lysyl side chain of lipid II. FemX adds the first glycyl unit, FemA the second and third unit, and FemB adds the fourth and fifth glycyl unit to complete the pentaglycine-bridge. Enzyme FemA interacts with the eukaryotic-like serine/threonine kinase Stk, but is not phosphorylated by it. FemA and FemB interact with Stk and with cell wall synthesis enzymes (MurG, Pbp1, Pbp2), Mgt, LytH, RodA, FtsW and cell division proteins (DivIB, DivIC, EzrA). FemA and FemB interact with each other and also form homodimers, which is not the case for FemX. In contrast to FemX, the subsequent enzymes FemA or FemB are non-essential |
760162 |
