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.

similar to adenylation domain of plipastatin synthase (PpsD). This family of the adenylation (A) domain of nonribosomal peptide synthases (NRPS) includes bacitracin synthetase 1 (BacA) in Bacillus licheniformis, tyrocidine synthetase in Brevibacillus brevis, plipastatin synthase (PpsD, an important antifungal protein) in Bacillus subtilis and mannopeptimycin peptide synthetase (MppB) in Streptomyces hygroscopicus. Plipastatin has strong fungitoxic activity and is involved in inhibition of phospholipase A2 and biofilm formation. Bacitracin, a mixture of related cyclic peptides, is used as a polypeptide antibiotic while function of tyrocidine is thought to be regulation of sporulation. MppB is involved in biosynthetic pathway of mannopeptimycin, a novel class of mannosylated lipoglycopeptides. 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.

similar to adenylation domain of plipastatin synthase (PpsD). This family of the adenylation (A) domain of nonribosomal peptide synthases (NRPS) includes bacitracin synthetase 1 (BacA) in Bacillus licheniformis, tyrocidine synthetase in Brevibacillus brevis, plipastatin synthase (PpsD, an important antifungal protein) in Bacillus subtilis and mannopeptimycin peptide synthetase (MppB) in Streptomyces hygroscopicus. Plipastatin has strong fungitoxic activity and is involved in inhibition of phospholipase A2 and biofilm formation. Bacitracin, a mixture of related cyclic peptides, is used as a polypeptide antibiotic while function of tyrocidine is thought to be regulation of sporulation. MppB is involved in biosynthetic pathway of mannopeptimycin, a novel class of mannosylated lipoglycopeptides. 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.

similar to adenylation domain of plipastatin synthase (PpsD). This family of the adenylation (A) domain of nonribosomal peptide synthases (NRPS) includes bacitracin synthetase 1 (BacA) in Bacillus licheniformis, tyrocidine synthetase in Brevibacillus brevis, plipastatin synthase (PpsD, an important antifungal protein) in Bacillus subtilis and mannopeptimycin peptide synthetase (MppB) in Streptomyces hygroscopicus. Plipastatin has strong fungitoxic activity and is involved in inhibition of phospholipase A2 and biofilm formation. Bacitracin, a mixture of related cyclic peptides, is used as a polypeptide antibiotic while function of tyrocidine is thought to be regulation of sporulation. MppB is involved in biosynthetic pathway of mannopeptimycin, a novel class of mannosylated lipoglycopeptides. 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.

LCL-type Condensation (C) domain of non-ribosomal peptide synthetases(NRPSs) and similar domains including the C-domain of SgcC5, a free-standing NRPS with both ester- and amide- bond forming activity. LCL-type Condensation (C) domains catalyze peptide bond formation between two L-amino acids, ((L)C(L)). C-domains of NRPSs catalyze peptide bond formation within (usually) large multi-modular enzymatic complexes. NRPS can use a large variety of acyl monomers (approximately 500 different possible monomer substrates as opposed to the 20 standard amino acids in ribosomal protein synthesis) to construct bioactive secondary metabolites of 2 to 18 units long (with various activities such as antibiotic, antifungal, antitumor and immunosuppression). In addition to the LCL-type, there are various subtypes of C-domains such as the DCL-type which links an L-amino acid to the D-amino acid at the end of a growing peptide, starter C-domains which acylate the first amino acid with a beta-hydroxy carboxylic acid, and heterocyclization (Cyc) domains which catalyze both peptide bond formation and cyclization of Cys, Ser, or Thr residues. Typically, an NRPS module consists of an adenylation domain, a peptidyl carrier protein (PCP) domain (also known as thiolation (T) domain) and a C-domain. NRPS modules may also include specialized domains such as the terminal-module thioesterase (Te) domain that releases the product via hydrolysis or macrocyclization and any of various C-domain family members such as the epimerization (E) domain, the ester-bond forming C-domain, dual E/C (epimerization and condensation) domains, and the X-domain. Streptomyces globisporus SgcC5 is a free-standing NRPS condensation enzyme (rather than a modular NRPS), which catalyzes the condensation between the SgcC2-tethered (S)-3-chloro-5-hydroxy-beta-tyrosine and (R)-1phenyl-1,2-ethanediol, forming an ester bond, during the synthesis of the chromoprotein enediyne antitumor antibiotic C-1027. It has some acceptor substrate promiscuity as it has been shown to also catalyze the formation of an amide bond between SgcC2-tethered (S)-3-chloro-5-hydroxy-beta-tyrosine and a mimic of the enediyne core acceptor substrate having an amine at its C-2 position. C-domains typically have a conserved HHxxxD motif at the active site; mutations in this motif can abolish or diminish condensation activity. An HHxx[SAG]DGxSx(6)[ED] motif is characteristic of LCL-type C-domains.

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

Crystalstructure of a 5-domain construct of LgrA in the substrate donation state [Brevibacillus parabrevis],6MG0_A Crystal structure of a 5-domain construct of LgrA in the thiolation state [Brevibacillus parabrevis],6MG0_B Crystal structure of a 5-domain construct of LgrA in the thiolation state [Brevibacillus parabrevis]

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

Crystalstructure of a cross-module fragment from the dimodular NRPS DhbF [Geobacillus sp. Y4.1MC1]

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]

Plipastatin synthase subunit D OS=Bacillus subtilis (strain 168) OX=224308 GN=ppsD PE=1 SV=2

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

Chondramide synthase cmdD OS=Chondromyces crocatus OX=52 GN=cmdD PE=1 SV=1

Surfactin synthase subunit 2 OS=Bacillus subtilis (strain 168) OX=224308 GN=srfAB PE=1 SV=3

Linear gramicidin synthase subunit C OS=Brevibacillus parabrevis OX=54914 GN=lgrC PE=3 SV=1