Structural and functional studies of protein complexes from Ruminococcus flavefaciens cellulosome

• Grant number: 10/19240-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: April 01, 2011
• End date: June 30, 2015
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Richard Charles Garratt
• Grantee: Juliana Cheleski Wiggers
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated scholarship(s): 13/24972-1 - Cryo-electron tomography to visualize macromolecular organization, BE.EP.PD

Abstract

The cellulosome is an intricate multienzyme complex, designed for efficient degradation of polysaccharides found in cell walls, notably cellulose. The supramolecular architecture of cellulosome is the recruitment of various hydrolytic enzymes in a non-catalytic subunit called escafoldina. The recognition and integration of the complex occurs through the strong interaction between two protein domains exist in the enzyme subunits (dockerina) and escafoldina (cohesin). The non-catalytic subunit is usually anchored to the cell surface and has a substrate recognition module polysaccharide, being cellulosome an ideal nanomachine for cellulose degradation. The structural organization of the cellulosome of different bacteria that has the modules types I and II is a direct consequence of two specific types of interactions existing in pair-dockerina cohesin. However, the cellulosome complex of Ruminococcus flavefaciens, couple dockerina-cohesin differ both in sequence and structure in relation to the types I and II, classified as type III. Given the lack of information on the interactions found in the cellulosome of R. flavefaciens, this project focuses on structural and functional studies of its heterodimer cohesin-dockerina. The determination of three-dimensional structures of complexes of the type III show in detail its mode of interaction, the main paradigm elucidating the structural organization of the single complex that employs such modules. On the other hand, structural information of the molecular determinants for the interaction of the type III domains increases the range of opportunities for employment of these versatile building blocks. Among the many applications, the incorporation of the structural architecture of the cellulosome to increase the efficiency of the enzymes can lead to development of economically viable processes, such as its use in the optimization of production of bioethanol. (AU)