Mining the whole genome sequence of Streptomyces cyaneofuscatus strain CTM50504 isolated from the Aïn El-Atrous hot spring, Tunisia, for the discovery of extremozymes: promising properties of protease activity

Abstract

Next-generation sequencing (NGS) methods allow for the generation of data leading to a greater understanding of the potential functionality and dynamics of microorganisms within their biotopes. The enormous volume of data that NGS produces necessitates understanding structural and functional genomics through the application of various omics techniques. Streptomyces cyaneofuscatus CTM50504 is a potential extracellular hydrolase producer isolated from a terrestrial hot spring, Aïn El-Atrous, Korbous (Nabeul, Tunisia). This strain can grow at 50 ◦ C and a pH range of 6–9. It requires the presence of NaCl for growth and secretes proteases, lipases, phospholipases, amylases, and chitinases. Whole-genome sequence (WGS) analysis was performed on strain CTM50504 to identify protein-encoding genes, including hydrolases. The genome sequence was assembled into 858-contigs with an average G + C content of 71 % and a total length of 8,591,922-bp. Genome annotation revealed 770- protein-coding genes with 323 open reading frames encoding hydrolases, including 179-proteases, 20-lipases, 10-phospholipases, 5-amylases, and 5-chitinases. The gene encoding a serine alkaline protease (SCKP) was heterologously expressed in Escherichia coli. The recombinant SCKP (rSCKP) was purified by affinity chromatography, and its biochemical properties were determined. Molecular dynamics simulations provided deeper insights into how key amino acids contribute to substrate binding and elucidated the basis of substrate selectivity.