In silico Structural, Functional and Phylogenetic Analyses of cellulase from Ruminococcus albus

Abstract

Background Cellulose is the primary component of the plant cell wall and an important source of energy for the ruminant and microbial protein synthesis in the rumen. Cell wall content is digested by anaerobic fermentation activity mainly of bacteria belonging to species Fibrobacter succinogenes, Ruminicoccus albus, Ruminococcus flavefaciens, and Butyrivibrio fibrisolvens. Bacteria belonging to the species Ruminococcus albus contain cellulosomes that enable it to adhere to and digest cellulose, and its genome encodes cellulases and hemicellulases. This study aimed to perform an in silico comparative characterization and functional analysis of cellulase from Ruminococcus albus to explore physicochemical properties and to estimate primary, secondary, and tertiary structure using various bio-computational tools. The protein sequences of cellulases belonging to 6 different Ruminococcus albus strains were retrieved using UniProt. In in silico composition of amino acids, basic physicochemical characteristics were analyzed using ProtParam and Protscale. Multiple sequence alignment of retrieved sequences was performed using Clustal Omega and the phylogenetic tree was constructed using Mega X software. Bioinformatics tools are used to better understand and determine the 3D structure of cellulase. The predicted model was refined by ModRefiner. Structure alignment between the best-predicted model and the template is applied to evaluate the similarity between structures. Results In this study are demonstrated several physicochemical characteristics of the cellulase enzyme. The instability index values indicate that the proteins are highly stable. Proteins are dominated by random coils and alpha helixes. The aliphatic index was higher than 71 providing information that the proteins are highly thermostable. No transmembrane domain was found in the protein, and the enzyme is extracellular and moderately acidic. The best tertiary structure model of the enzyme was obtained by the use of Raptor X, which was refined by ModRefiner. Raptor X suggested the 6Q1I_A as one of the best homologous templates for the predicted 3D protein structure. Ramachandran plot analysis showed that 90.1% of amino acid residues are within the most favored regions. Conclusions This study provides for the first time insights about the physicochemical properties, structure, and function of cellulase, from Ruminococcus albus, that will help for detection and identification of such enzyme in vivo or in silico.

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Application of Phytochemicals To Combat Fungal Pathogens of Pulses: An Approach toward Inhibition of Fungal Propagation and Invasin Activity

“…20 The Ramachandran plot of the model cellulase, xylanase, and amylase proteins showed that about 99.00, 100, and 99.5% amino acids are in the allowed region, showing higher steadiness of the model proteins. 43 44 From this standpoint, in silico analysis was executed in the present study. Physiochemical properties obtained from Protparam showed that the model cellulase, xylanase, and amylase had an instability index of 26.66, 34.69, and 13.23, respectively, which suggest the steadiness of the proteins under in vitro conditions (Table 1).…”

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“…The protein sequences of many enzymes like peroxidases [25][26][27], pectinases, proteases [28], lipases [29], phytases, polyphenol oxidases [15], and cellulases [29] have been assessed and analyzed using bioinformatics tools. The current study used various bioinformatic tools to analyze the protein sequences of industrially important enzyme catalases from various plant sources.…”