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Title: STRUCTURAL AND FUNCTIONAL IMPLICATIONS OF C-TERMINAL REGION OF BOVINE B-CASEIN

Author
item Qi, Phoebe
item FARRELL, HAROLD - RETIRED/LS/DPPRU-USDA,ARS

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/2/2004
Publication Date: 4/1/2004
Citation: Qi, P.X., Farrell, H.M. 2004. Structural and functional implications of C-Terminal Region of Bovine-Beta Casein. (abstract). 48th Biophysical Society Ann. Mtg. 86:491a.

Interpretive Summary: n/a

Technical Abstract: To understand the importance of the C-terminal region on the structure and function of bovine B-casein, fragment 1-192 (f1-192) of B-casein obtained by chymosin digestion was examined and characterized using circular dichroism (CD) and fluorescence spectroscopy under various temperature and solvent conditions. Analytical ultracentrifugation results indicated negligible degree of self-association in f1-192 compared to the native protein from 2 degrees to 37 degrees C. Analysis of the far UV CD data revealed little change in the overall secondary structural content in f1-192 relative to native B-casein from 5 degrees to 70 degrees C. Near UV CD is nearly identical for the two proteins. Intrinsic tryptophan fluorescence was used to investigate the thermal and urea induced unfolding behavior. Results obtained in this work suggest possible secondary structural disruption of B-casein upon its C-terminal deletion. Furthermore, it has been demonstrated unambiguously that the C-terminal tail peptide (f193-209) is essential for the self-association and the formation of a complex with 8-anilino-1-naphthalene sulfonic acid (ANS). These results may provide further insights on the critical role of the C-terminal region in the natural cellular function of B-casein as well as in the whole casein micelle assembly.