Conformational changes of bovine beta-trypsin and trypsinogen induced by divalent ions: an energy-dispersive X-ray diffraction and functional study.
The radius of gyration (R(g)) of bovine trypsinogen and beta-trypsin was measured by an energy-dispersive X-ray technique as a function of Ca(2+) or SO(4)(2-) concentration; these results have been supplemented with measurements of association equilibrium constants of Ca(2+) to its binding site(s) on both serine proteases and some of their adducts (with an effector and/or an inhibitor). As a whole, all information reported in the present work demonstrates that: (i) the strains exerted by different ions on these proteases produce diverse structural modifications; and (ii) at least in the case of Ca(2+), the changes in R(g) can be ascribed to the direct interaction of the binding site(s) on the protein matrix with the cation.
Caracciolo
G
G
Dipartimento di Chimica, Università di Roma La Sapienza and INFM, 00185 Roma, Italy. a.congiu@caspur.it
Martelli
A
A
Boumis
G
G
Bellelli
A
A
Caminiti
R
R
Congiu-Castellano
A
A
Amiconi
G
G
D000818:Animals; D002118:Calcium / Q000737:chemistry*; D002417:Cattle; D007477:Ions; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D014357:Trypsin / Q000032:analysis / Q000737:chemistry*; D014362:Trypsinogen / Q000032:analysis / Q000737:chemistry*; D014961:X-Ray Diffraction
D007477:Ions; D014362:Trypsinogen; D014357:Trypsin; D002118:Calcium