Summary:
"Phenylethylamine regulator," FeaR, is considered an activator of phenylacetate synthesis from 2-phenylethylamine (PEA). This regulator is regulated by catabolic repression, and highly expressed in the presence of succinate [3]. FeaR controls expression of a pathway for the degradation of potentially toxic aromatic compounds [2]. It is induced by tyramine, and in the absence of glucose, it activates the expression of amine oxidase and phenylacetaldehyde dehydrogenase, proteins involved in 2-phenylethylamine catabolism [1, 2, 4]. Although it has not been possible to test the ligand binding to FeaR, these data and those of others suggest that it is a substrate or intermediate of the TynA/FeaB pathway, as it is more likely that an aldehyde (tyramine) is the direct inducer for the PEA catabolic pathway and a likely coeffector of FeaR [2].
FeaR belongs to the AraC/XylS family of transcriptional regulators [1, 3].
This protein consists of two domains, an amino-terminal domain (NTD) involved in co-inducer recognition and dimerization and a carboxy-terminal domain (CTD) that contains a potential helix-turn-helix DNA-binding motif
[1, 3]. Activation by FeaR requires the NTD, which could function as an inhibitor of the CTD in the absence of the coactivator
[2].
The region at positions 12-185 in FeaR appears to be a ligand-binding domain,; specifically, the residues A81 and M83, which are part of a beta-barrel structure, appear to be involved in binding of ligands that could be the aromatic aldehydes derived from amines
[5]
The FeaR-binding site is a direct repeat of two 16-bp elements with the core consensus sequence TGKCA-N
8-MAA (where K is G or T and M is C or A) for each 16-bp sequence
[2].
[EXP-IEP-GENE-EXPRESSION-ANALYSIS] Gene expression analysis