Steady-state fluorescence and circular dichroism of trout hemoglobins I and IV interacting with tributyltin

• Published in: Proteins, structure, function, and bioinformatics structure, function, and bioinformatics, 1999-03, Vol.34 (4), p.443-452
• Main Authors: Zolese, G., Gabbianelli, R., Caulini, G.C., Bertoli, E., Falcioni, G.
• Format: Article
• Language: English
• Subjects: 1-anilinonaphthalene-8-sulfonic acid; Anilino Naphthalenesulfonates - chemistry; Animals; Circular Dichroism; Dose-Response Relationship, Drug; HbI; HbIV; heme; Hemoglobins - metabolism; Hemoglobins, Abnormal - metabolism; Hydrogen-Ion Concentration; Oncorhynchus mykiss; Spectrometry, Fluorescence; Temperature; Time Factors; Trialkyltin Compounds - metabolism; tryptophan
• ISSN: 0887-3585; 1097-0134
• DOI: 10.1002/(SICI)1097-0134(19990301)34:4<443::AID-PROT4>3.0.CO;2-D

The effect of tributyltin chloride (TBTC) on rainbow trout (Salmo irideus) hemoglobin I (HbI) and hemoglobin IV (HbIV) was characterized by the steady‐state fluorescence of intrinsic and extrinsic fluorescent probes. The fluorescence emission spectrum (λex 280 nm) is greatly increased in intensity by the presence of the organotin in both proteins. Circular dichroism spectra in the same samples show a small decrease in θ222, a measure correlated with the percentage of the α‐helical content. Morever, important changes in near‐UV, Soret, and visible regions of CD were induced by TBTC. The correlation of data obtained with trout hemoglobins (HbI and HbIV) with similar measurements on globins suggests that the presence of heme is necessary for the interaction of the organotin compound with the proteins. Proteins 1999;34:443–452. © 1999 Wiley‐Liss, Inc.