Structural perturbation of alphaB-crystallin by zinc and temperature related to its chaperone-like activity.
alphaB-crystallin is a small heat shock protein that shows chaperone-like activity, as it protects the aggregation of denatured proteins. In this work, the possible relationships between structural characteristics and the biological activity of alphaB-crystallin were investigated on the native protein and on the protein undergoing the separate effects of metal ligation and temperature. The chaperone-like activity of alphaB-crystallin increased in the presence of zinc and when temperature was increased. By using fluorescent probes to monitor hydrophobic surfaces on alphaB-crystallin, it was found that exposed hydrophobic patches on the protein surface increased significantly both in the presence of zinc and when the temperature was raised from 25 to 37 degrees C. The zinc-induced increased exposure of lipophilic residues is in agreement with theoretical calculations performed on 3D-models of monomeric alphaB-crystallin, and may be significant to its increased biological activity.
Dipartimento di Scienze Farmaceutiche, Università di Pisa, Via Bonanno 6, 56126 Pisa, Italy. alec@farm.unipi.it
Alessio
A
Coi
Anna Maria
AM
Bianucci
Francesco
F
Bonomi
Patrizia
P
Rasmussen
Giovanni Maria
GM
Mura
Maria Luisa
ML
Ganadu
D000818:Animals; D005456:Fluorescent Dyes / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D018832:Molecular Chaperones / Q000737:chemistry*; D011489:Protein Denaturation; D015032:Zinc / Q000737:chemistry*; D038203:alpha-Crystallin B Chain / Q000737:chemistry*
D005456:Fluorescent Dyes; D018832:Molecular Chaperones; D038203:alpha-Crystallin B Chain; D015032:Zinc