@article {Kumar2018,
	title = {Novel insights into the degradation of β-1,3-glucans by the cellulosome of Clostridium thermocellum revealed by structure and function studies of a family 81 glycoside hydrolase},
	journal = {International Journal of Biological Macromolecules},
	year = {2018},
	note = {n/a},
	pages = {-},
	abstract = {<p>Abstract The family 81 glycoside hydrolase (GH81) from Clostridium thermocellum is a β-1,3-glucanase belonging to cellulosomal complex. The gene encoding \{GH81\} from Clostridium thermocellum (CtLam81A) was cloned and expressed displaying a molecular mass of ~82 kDa. CtLam81A showed maximum activity against laminarin (100 U/mg), followed by curdlan (65 U/mg), at pH 7.0 and 75 {\textdegree}C. CtLam81A displayed Km, 2.1 {\textpm} 0.12 mg/ml and Vmax, 109 {\textpm} 1.8 U/mg, against laminarin under optimized conditions. CtLam81A activity was significantly enhanced by Ca2+ or Mg2+ ions. Melting curve analysis of CtLam81A showed an increase in melting temperature from 91 {\textdegree}C to 96 {\textdegree}C by Ca2+ or Mg2+ ions and decreased to 82 {\textdegree}C by EDTA, indicating that Ca2+ and Mg2+ ions may be involved in catalysis and in maintaining structural integrity. \{TLC\} and MALDI-TOF analysis of β-1,3-glucan hydrolysed products released initially, showed β-1,3-glucan-oligosaccharides degree of polymerization (DP) from \{DP2\} to DP7, confirming an endo-mode of action. The catalytically inactive mutant CtLam81A-E515A generated by site-directed mutagenesis was co-crystallized and tetragonal crystals diffracting up to 1.4 {\r A} resolution were obtained. CtLam81A-E515A contained 15 α-helices and 38 β-strands forming a four-domain structure viz. a β-sandwich domain I at N-terminal, an α/β-domain II, an (α/α)6 barrel domain III, and a small 5-stranded β-sandwich domain IV.</p>
},
	keywords = {X-ray crystallography},
	issn = {0141-8130},
	doi = {https://doi.org/10.1016/j.ijbiomac.2018.06.003},
	url = {https://www.sciencedirect.com/science/article/pii/S0141813018322384},
	author = {Krishan Kumar and Correia, M{\'a}rcia and Virg{\'\i}nia R. Pires and Arun Dhillon and Kedar Sharma and Vikky Rajulapati and Fontes, Carlos M. G. A. and Ana Lu{\'\i}sa Carvalho and Goyal, Arun}
}
