The adenylation domain of nonribosomal peptide synthetases (NRPS). The adenylation (A) domain of NRPS recognizes a specific amino acid or hydroxy acid and activates it as an (amino) acyl adenylate by hydrolysis of ATP. The activated acyl moiety then forms a thioester bond to the enzyme-bound cofactor phosphopantetheine of a peptidyl carrier protein domain. NRPSs are large multifunctional enzymes which synthesize many therapeutically useful peptides in bacteria and fungi via a template-directed, nucleic acid independent nonribosomal mechanism. These natural products include antibiotics, immunosuppressants, plant and animal toxins, and enzyme inhibitors. NRPS has a distinct modular structure in which each module is responsible for the recognition, activation, and in some cases, modification of a single amino acid residue of the final peptide product. The modules can be subdivided into domains that catalyze specific biochemical reactions.

bacitracin synthetase and related proteins. This family of the adenylation (A) domain of nonribosomal peptide synthases (NRPS) includes bacitracin synthetases 1, 2, and 3 (BA1, also known as ATP-dependent cysteine adenylase or cysteine activase, BA2, also known as ATP-dependent lysine adenylase or lysine activase, and BA3, also known as ATP-dependent isoleucine adenylase or isoleucine activase) in Bacilli. Bacitracin is a mixture of related cyclic peptides used as a polypeptide antibiotic. This family also includes gramicidin synthetase 1 involved in synthesis of the cyclic peptide antibiotic gramicidin S via activation of phenylalanine. NRPSs are large multifunctional enzymes which synthesize many therapeutically useful peptides in bacteria and fungi via a template-directed, nucleic acid independent nonribosomal mechanism. These natural products include antibiotics, immunosuppressants, plant and animal toxins, and enzyme inhibitors. NRPS has a distinct modular structure in which each module is responsible for the recognition, activation, and in some cases, modification of a single amino acid residue of the final peptide product. The modules can be subdivided into domains that catalyze specific biochemical reactions.

The adenylation domain of nonribosomal peptide synthetases (NRPS), including Bacillus subtilis termination module Surfactin (SrfA-C). The adenylation (A) domain of NRPS recognizes a specific amino acid or hydroxy acid and activates it as an (amino) acyl adenylate by hydrolysis of ATP. The activated acyl moiety then forms a thioester to the enzyme-bound cofactor phosphopantetheine of a peptidyl carrier protein domain. NRPSs are large multifunctional enzymes which synthesize many therapeutically useful peptides in bacteria and fungi via a template-directed, nucleic acid independent nonribosomal mechanism. These natural products include antibiotics, immunosuppressants, plant and animal toxins, and enzyme inhibitors. NRPS has a distinct modular structure in which each module is responsible for the recognition, activation, and, in some cases, modification of a single amino acid residue of the final peptide product. The modules can be subdivided into domains that catalyze specific biochemical reactions. This family includes the adenylation domain of the Bacillus subtilis termination module (Surfactin domain, SrfA-C) which recognizes a specific amino acid building block, which is then activated and transferred to the terminal thiol of the 4'-phosphopantetheine (Ppan) arm of the downstream peptidyl carrier protein (PCP) domain.

peptide synthase; Provisional

amino acid adenylation domain. This model represents a domain responsible for the specific recognition of amino acids and activation as adenylyl amino acids. The reaction catalyzed is aa + ATP -> aa-AMP + PPi. These domains are usually found as components of multi-domain non-ribosomal peptide synthetases and are usually called "A-domains" in that context. A-domains are almost invariably followed by "T-domains" (thiolation domains, pfam00550) to which the amino acid adenylate is transferred as a thiol-ester to a bound pantetheine cofactor with the release of AMP (these are also called peptide carrier proteins, or PCPs. When the A-domain does not represent the first module (corresponding to the first amino acid in the product molecule) it is usually preceded by a "C-domain" (condensation domain, pfam00668) which catalyzes the ligation of two amino acid thiol-esters from neighboring modules. This domain is a subset of the AMP-binding domain found in Pfam (pfam00501) which also hits substrate--CoA ligases and luciferases. Sequences scoring in between trusted and noise for this model may be ambiguous as to whether they activate amino acids or other molecules lacking an alpha amino group.

Structureof surfactin A synthetase C (SrfA-C), a nonribosomal peptide synthetase termination module [Bacillus subtilis]

Crystalstructure of dimodular LgrA in a condensation state [Brevibacillus parabrevis],6MFZ_B Crystal structure of dimodular LgrA in a condensation state [Brevibacillus parabrevis]

Understandingbi-specificity of A-domains [Planktothrix agardhii],4D4H_A Understanding bi-specificity of A-domains [Planktothrix agardhii],4D4I_A Understanding bi-specificity of A-domains [Planktothrix agardhii],4D56_A Understanding bi-specificity of A-domains [Planktothrix agardhii],4D57_A Understanding bi-specificity of A-domains [Planktothrix agardhii]

PhenylalanineActivating Domain Of Gramicidin Synthetase 1 In A Complex With Amp And Phenylalanine [Brevibacillus brevis],1AMU_B Phenylalanine Activating Domain Of Gramicidin Synthetase 1 In A Complex With Amp And Phenylalanine [Brevibacillus brevis]

Thestructure of condensation and adenylation domains of teixobactin-producing nonribosomal peptide synthetase Txo2 serine module [Eleftheria terrae],6P1J_B The structure of condensation and adenylation domains of teixobactin-producing nonribosomal peptide synthetase Txo2 serine module [Eleftheria terrae]

Linear gramicidin synthase subunit D OS=Brevibacillus parabrevis OX=54914 GN=lgrD PE=1 SV=1

Tyrocidine synthase 2 OS=Brevibacillus parabrevis OX=54914 GN=tycB PE=1 SV=1

Plipastatin synthase subunit B OS=Bacillus subtilis (strain 168) OX=224308 GN=ppsB PE=1 SV=1

Tyrocidine synthase 1 OS=Brevibacillus parabrevis OX=54914 GN=tycA PE=1 SV=2

Bacitracin synthase 1 OS=Bacillus licheniformis OX=1402 GN=bacA PE=3 SV=1