Molecular analysis of recombinant collagenase from Bacillus siamensis strain Z1: Gene Cloning, expression and in-silico characterization

This study focuses on gene cloning, expression, biochemical and analytical characterization along with structural and functional characterization of collagenase followed with molecular docking, dynamics study and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA). The collagenase gene identified from the genome of the novel collagenase Bacillus siamensis strain Z1 is introduced into E.coli DH5α, subsequently expressed in E.coli BL21 (DE3) withisopropyl β −d – 1 − thiogalactopyranoside(IPTG) induction and further affinity purified yielding in ∼ 89.4 kDa recombinant collagenase which demonstrated alkali characteristics and thermostability determined by thermodynamic parameters. Recombinant collagenase revealed good stability when exposed to diverse biochemical components. The recombinant collagenase identity was confirmed through matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) showing specific mass peaks and via N-terminal sequence analysis as MTAVNQTISK. Moreover, the concluded N-terminal amino acid sequence from Edman degradation displayed significant resemblance. The structural and functional analysisof recombinant collagenase was analysed by Circular dichroism (CD), Proton nuclear magnetic resonance (¹H NMR) spectrometry and Thermogravimetric analysis (TGA). The recombinant collagenase also showed gelatin liquefaction ability. The collagenase gene sequence is also assessed for structural and functional characterizations by using various computational tools and revealed its classification in U32 family peptidase. A Grand average of hydropathicity index (GRAVY) score of −0.295 and instability index of 37.22 was obtained. Homology model of collagenase gene was generated by employing SWISS-MODEL and structure analysis by Ramachandran plot. Molecular docking of modelled collagenase with four different substrates was carried out by PyRx and Autodocking. Highest docking score of −12.7 kcal/mol was obtained for Alaska pollock hydroxyproline containing marine collagen peptide (APHCP). Subsequently, Molecular dynamics and simulations for highest score docked complex was assessed using GROningenMAchine for Chemical Simulations (GROMACS).