title: Critical Role of a Loop at C-Terminal Domain on the Conformational Stability and Catalytic Efficiency of Chondroitinase ABC I.
abstract: We used a combination of protein engineering and spectroscopic methods to investigate the effect of a long length loop on the conformational stability and activity of chondroitinase ABC I. This study involves manipulation of interactions around Asp(689) as a key residue in the central region of the loop containing residues 681-695 located at C-terminal domain of the enzyme. According to the equilibrium unfolding experiments and considering thermodynamic m value and ΔG(H2O), we found that the folded state of H700N, L701T, and H700N/L701T are more compact relative to the folded state of wild-type protein and they become stabilized upon mutation. However, the compactness and stability of other variants are less than those of wild-type protein. According to enzyme activity measurements, we found that the catalytic efficiency of structurally stabilized variants is decreased, while that of destabilized mutants is improved.
authors: Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran.
authors: S
authors: S
authors: Akram Shirdel
authors: Khosrow
authors: K
authors: Khalifeh
authors: Abolfazl
authors: A
authors: Golestani
authors: Bijan
authors: B
authors: Ranjbar
authors: Khosro
authors: K
authors: Khajeh
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D019765:Chondroitin ABC Lyase / Q000737:chemistry* / Q000235:genetics; D004795:Enzyme Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D011514:Proteus vulgaris / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D019765:Chondroitin ABC Lyase