Participatory role of zinc in structural and functional characterization of bioremediase: a unique thermostable microbial silica leaching protein

Abstract

A unique protein, bioremediase (UniProt Knowledgebase Accession No.: P86277), isolated from a hot spring bacterium BKH1 (GenBank Accession No.: FJ177512), has shown to exhibit silica leaching activity when incorporated to prepare bio-concrete material. Matrix-assisted laser desorption ionization mass spectrometry analysis suggests that bioremediase is 78% homologous to bovine carbonic anhydrase II though it does not exhibit carbonic anhydrase-like activity. Bioinformatics study is performed for understanding the various physical and chemical parameters of the protein which predicts the involvement of zinc encircled by three histidine residues (His94, His96 and His119) at the active site of the protein. Isothermal titration calorimetric-based thermodynamic study on diethyl pyrocarbonate-modified protein recognizes the presence of Zn(2+) in the enzyme moiety. Exothermic to endothermic transition as observed during titration of the protein with Zn(2+) discloses that there are at least two binding sites for zinc within the protein moiety. Addition of Zn(2+) regains the activity of EDTA chelated bioremediase confirming the presence of extra binding site of Zn(2+) in the protein moiety. Revival of folding pattern of completely unfolded urea-treated protein by Zn(2+) explains the participatory role of zinc in structural stability of the protein. Restoration of the λ max in intrinsic fluorescence emission study of the urea-treated protein by Zn(2+) similarly confirms the involvement of Zn in the refolding of the protein. The utility of bioremediase for silica nanoparticles preparation is observed by field emission scanning electron microscopy.

A microbial protein-assisted silica ball comprising of silica-nanoparticles with plausible optical properties for multiple applications

“…The results suggested that SiO 2 -NPs assembled to from silica ball due to the interaction of bioremediase protein and TEOS solution. It similarly confirmed the successful synthesis of Si-NPs using bioremediase protein from TEOS as an organic precursor [14]. The synthesized Si-NPs were quite regular in shape and consistently dispersed as observed in both FE-SEM and TEM images.…”

“…The possible vibrational bands shown at 1097 cm -1 (ν as : Si-O) and 790 cm -1 (ν s : Si-O) were the two strong evidence of the formation of SiO 2 -NPs. The absorption bands appeared between 800 and 1269 cm -1 had been ascribed as a superimposition of assorted SiO 2 peaks, Si-OH bonding and residual organic groups [14]. The amorphous nature of prepared SiO 2 -NPs was confirmed from the XRD observation (Fig.…”

Biochemical Characterization and Validation of a Catalytic Site of a Highly Thermostable Ts2631 Endolysin from the Thermus scotoductus Phage vB_Tsc2631

“…In thermolysin from Bacillus thermoproteolyticus , a metalloprotease, a Zn 2+ ion plays a catalytic but not a structural role, and it does not contribute to the unusually high thermal stability of the enzyme [ 52 ]. However, a structural and functional role for Zn 2+ is known for other thermostable enzymes, namely bioremediase [ 53 ]. All Ts2631 endolysin substitution variants were soluble at 60°C, which is the temperature that the lytic activity tests were performed ( Fig 6B ).…”

Comparative analysis of microbial diversity in two hot springs of Bakreshwar, West Bengal, India

“…This has led to the isolation and identification of a number of metal-reducing bacteria. Three bacterial strains so isolated and partially characterized from water of the 65 °C hot spring consortium were found efficacious for enhancement of concrete strength, silica leaching activity and other industrial applications [7], [8], [9], [10], [11], [12].…”