| Type: | Family | Name: | 2,3-dihydroxybenzoate-AMP ligase |
| Description: | Siderophores are low molecular weight iron-chelating compounds synthesised by many bacteria to aid in the aquisition of this vital trace element []. Proteins in this entry are adenylation components of non-ribosomal peptide synthases (NRPSs) involved in the biosynthesis of siderophores. These proteins belong to the AMP-binding family and are mostly thought to activate 2,3-dihydroxybenzoate (DHB) by ligation of AMP from ATP with the release of pyrophosphate (ATP-PPi exchange). Enzymatic studies on the purified enzyme, 2,3DHB-AMP ligase of Escherichia coli, show that 2,3DHB efficiently supports the ATP-PPi exchange while other analogues can replace 2,3DHB, for example: salicyclic acid (o-hydrobenzoate); 2,4DHB and 2,5DHB; though the natural substrate 2,3DHB is by far the most efficient. Substrates such as 2,6DHB and 2,4,6THB do not support the ATP-PPi exchange and suggest significant steric interference by the 6-hyroxy side chain [].The crystal structure of 2,3-dihydroxybenzoate-AMP ligase () from Bacillus subtilishas been examined []. This protein is composed of a large N-terminal domain (~420 aa) and a more compact C-terminal domain (~110 aa), with an overall "hammer-and-anvil" fold similar to that of firefly luciferase []. The active site is located in a deep compartment located at the interface of the domains, with a p-loop thought to be involved in catalysis located at the entrance to the cavity. Relatively little conformational change was observed during catalysis. | Short Name: | DHB_AMP_lig |
