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.
Dipartimento di Chimica, Università di Roma La Sapienza and INFM, 00185 Roma, Italy. a.congiu@caspur.it
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G
Caracciolo
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Martelli
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G
Boumis
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Bellelli
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Caminiti
A
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Congiu-Castellano
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Amiconi
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