Role of ionic interactions and linker in the domain interaction and modulation of functional activity of hyaluronate lyases

Akhtar, Md. Sohail ; Bhakuni, Vinod (2007) Role of ionic interactions and linker in the domain interaction and modulation of functional activity of hyaluronate lyases Biochemical and Biophysical Research Communications, 353 (2). pp. 286-292. ISSN 0006-291X

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/S00062...

Related URL: http://dx.doi.org/10.1016/j.bbrc.2006.12.014

Abstract

Hyaluronate lyases from Streptococcus pneumoniae (SpnHL) and Streptococcus agalactiae (SagHL) are composed of four domains; N-terminal domain, spacer domain, α-domain and c-terminal domain, which are connected through peptide linkers. We have earlier shown that the recombinant α- and c-terminal domains of SpnHL/SagHL interact with each other even in absence of the linker and form a functional complex with enhanced enzymatic activity. Here, we looked into the role of ionic interactions in the enzyme stability and also the role of c-terminal domain and linker in the functional regulation. Domain swapping studies showed that the c-terminal domain does not bind directly to the substrate; instead the domain contributes to the interaction with the polymeric hyaluronan for catalysis. Furthermore, the substrate specificity exchanges with the size of catalytic cleft. The role of linker connecting α-domain to c-terminal domain was found to hold the c-terminal domain in a conformation suitable for achieving maximum activity.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Enzyme; Stability; Function; Domain
ID Code:21100
Deposited On:20 Nov 2010 09:10
Last Modified:17 Jan 2011 11:33

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