טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentShafat Itay
SubjectBiochemical Characterization of cpn60 and cpn10 from
Mycobacterium tuberculosis
DepartmentDepartment of Biotechnology and Food Engineering
Supervisor Professor Yechezkel Kashi


Abstract

Mycobacterium tuberculosis belongs to a unique group of organisms that express two copies of Heat Shock Protein 60kDa, or chaperones (cpn), instead of the usual single copy. The role of these two cpns, cpn60.1 and cpn60.2, in the cell biology is unknown, as is the relation between the two proteins and the co-chaperone cpn10. In-Vitro experiments using proteins over-expressed in E.coli failed to show characteristic chaperone properties of the cpn60s or characteristic structure of known cpn60s (a tetradecamer). Cpn10 though, proved to be a co-chaperone, facilitating renaturation of Urea-denatured MDH, successfully replacing the native GroES (E.coli cpn10) as a co-chaperone of GroEL (E.coli cpn60). In-Vivo experiments, using M.bovice BCG, which is closely related to M.tuberculosis, showed possible large structure of both cpn60.1 and cpn60.2. the nature of these structure/s is yet unknown.

The antigenic properties of cpn60.2, and its suspected involvement in diseases, such as tuberculosis and Adjuvant Arthritis (AA) (a disease in rats used as a model for Rheumatoid Arthritis (RA)), are well studied. Since AA is an autoimmune disease, we developed a mutant of  GroEL, expressing a rat-cpn60 peptide that was found to be involved in the development of tolerance to AA. This mutant will be used to study AA, and can be a forerunner tool for studying the fine properties and effects of the cpn60 proteins on the immune system.