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16  structures 1056  species 0  interactions 3105  sequences 12  architectures

Family: FemAB (PF02388)

Summary: FemAB family

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FemAB family Provide feedback

The femAB operon codes for two nearly identical approximately 50-kDa proteins involved in the formation of the Staphylococcal pentaglycine interpeptide bridge in peptidoglycan [1]. These proteins are also considered as a factor influencing the level of methicillin resistance [2].

Literature references

  1. Ehlert K, Schroder W, Labischinski H; , J Bacteriol 1997;179:7573-7576.: Specificities of FemA and FemB for different glycine residues: FemB cannot substitute for FemA in staphylococcal peptidoglycan pentaglycine side chain formation. PUBMED:9393725 EPMC:9393725

  2. Vannuffel P, Heusterspreute M, Bouyer M, Vandercam B, Philippe M, Gala JL; , Res Microbiol 1999;150:129-141.: Molecular characterization of femA from Staphylococcus hominis and Staphylococcus saprophyticus, and femA-based discrimination of staphylococcal species. PUBMED:10209768 EPMC:10209768

  3. Berger-Bachi B, Barberis-Maino L, Strassle A, Kayser FH; , Mol Gen Genet 1989;219:263-269.: FemA, a host-mediated factor essential for methicillin resistance in Staphylococcus aureus: molecular cloning and characterization. PUBMED:2559314 EPMC:2559314

  4. Stranden AM, Ehlert K, Labischinski H, Berger-Bachi B; , J Bacteriol 1997;179:9-16.: Cell wall monoglycine cross-bridges and methicillin hypersusceptibility in a femAB null mutant of methicillin-resistant Staphylococcus aureus. PUBMED:8981974 EPMC:8981974

  5. Henze U, Sidow T, Wecke J, Labischinski H, Berger-Bachi B; , J Bacteriol 1993;175:1612-1620.: Influence of femB on methicillin resistance and peptidoglycan metabolism in Staphylococcus aureus. PUBMED:8383661 EPMC:8383661

Internal database links

External database links

This tab holds annotation information from the InterPro database.

InterPro entry IPR003447

The entry represents the FemABX peptidyl transferase family.

FemABX peptidyl transferases catalyse the incorporation of amino acid(s) into the interchain peptide bridge of peptidoglycan using aminoacyl-tRNA as the amino acid donor, a reaction involved in the synthesis of the bacterial cell wall. The femABX enzymes catalyse the addition of amino acids to a peptidoglycan precursor, which in most cases is a lipid-linked sugar pentapeptide or, alternatively, a soluble nucleotide precursor for W. viridescens femX. The resulting branched peptide chain consists of one to five amino acids and is cross-linked to a pentapeptide of a neighbouring disaccharide chain by a transpeptidase in the final step of peptidoglycan synthesis. The interchain peptide and the femABX enzymes for their synthesis are found in several Gram-positive bacteria and in some Gram-negative, mainly pathogenic species. The femABX transferases differ by type, position and number of amino acids that are incoporated into the interchain. Some femABX proteins function as immunity factors that protect producers of interpeptide-specific endopeptidases against their own products. In addition, the interpeptide plays an important role in cell separation and virulence [ PUBMED:11083873 , PUBMED:12604510 , PUBMED:12679335 , PUBMED:14962386 ].

Some proteins known to belong to the femABX peptidyl transferase family:

  • Staphylococcal femA and femB, factors essential for expression of methicillin resistance. FemA adds glycines 2 and 3 of the pentaglycine interpeptide, while femB adds glycines 4 and 5.
  • Staphylococcal fmhB (for fem homologue) or femX, which incorporates the first glycine of the pentaglycine interchain peptide in peptidoglycan.
  • Weissella viridescens femX, which catalyses the transfer of an L-alanine from Ala-tRNA to the epsilon-amino group of L-lysine of UDP-MurNAc pentapeptide [ PUBMED:12679335 , PUBMED:14962386 ].
  • Streptococcus pneumoniae fibA/murM and fibB/murN, which synthesize branched structured cell wall muropeptides that are strain-specific.
  • Staphylococcus capitis epr (endopeptidase resistance), which renders the cells resistant to glycylglycine endopeptidase by increasing the serine content and decreasing the glycine content of the interpeptide chains.

Gene Ontology

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Domain organisation

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You can also download a FASTA format file containing the full-length sequences for all sequences in the full alignment.

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This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.

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Curation and family details

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Curation View help on the curation process

Seed source: Pfam-B_1214 (release 5.2)
Previous IDs: none
Type: Family
Sequence Ontology: SO:0100021
Author: Bateman A , Mian N
Number in seed: 21
Number in full: 3105
Average length of the domain: 200.3 aa
Average identity of full alignment: 16 %
Average coverage of the sequence by the domain: 90.27 %

HMM information View help on HMM parameters

HMM build commands:
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 61295632 -E 1000 --cpu 4 HMM pfamseq
Model details:
Parameter Sequence Domain
Gathering cut-off 24.0 24.0
Trusted cut-off 24.0 24.0
Noise cut-off 23.9 23.9
Model length: 408
Family (HMM) version: 19
Download: download the raw HMM for this family

Species distribution

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Archea Archea Eukaryota Eukaryota
Bacteria Bacteria Other sequences Other sequences
Viruses Viruses Unclassified Unclassified
Viroids Viroids Unclassified sequence Unclassified sequence


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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the FemAB domain has been found. There are 16 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein sequence.

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