Identification of a putative keratinase gene and analysis of a peptidase S8 Family in a hyperthermophilic, Fervidobacterium sp. Strain FC2004 in Thailand

Abstract

A hyperthermophilic Fervidobacterium sp. strain FC2004 was previously isolated from a hot spring in Thailand. A putative gene encoding a proenzyme named in this study ¿ProA1¿ was identified from shotgun sequencing of genomic DNA of the strain FC2004. Predicted 3D-molecule contains a non-homologous signal peptide, a propeptide domain (PD), a catalytic domain (CD) with the typical catalytic triad residues of D169, H207 and S379, and a substrate binding domain (SD). Unlike fervidolysin and islandisin, the ProA1 completely lacks the SD2 domain. Phylogenetic analysis suggests that the ProA1 might be an intermediate isoform between high molecular weight and low molecular weight peptidase S8_subtilases. Although, the strain FC2004 is able to degrade pieces of native feather at high temperature, whether or not the mature ProA1 is active on keratin, the SD plays a role in hydrolyzing keratin substrate and the strain FC2004 might carry a second serine protease with two SDs remains to be investigated.