Study of Chaperone-Like Activity of Human Haptoglobin: Conformational Changes under Heat Shock Conditions and Localization of Interaction Sites

• Published in: Biological chemistry Vol. 383; no. 10; pp. 1667 - 1676
• Main Authors: Ettrich, R., Brandt, W., Kopecký, V., Baumruk, V., Hofbauerová, K., Pavlícek, Z.
• Format: Journal Article
• Language: English
• Published: Germany Walter de Gruyter 01.10.2002
• Subjects: Amino Acid Sequence; Binding Sites; Catalase - chemistry; Haptoglobins - chemistry; Haptoglobins - metabolism; Heat-Shock Proteins - chemistry; Heat-Shock Proteins - metabolism; Hemoglobins - chemistry; Hot Temperature; Humans; Models, Molecular; Molecular Chaperones - chemistry; Molecular Chaperones - metabolism; Molecular Sequence Data; Protein Denaturation; Protein Structure, Secondary; Sequence Alignment; Sequence Homology, Amino Acid; Solvents - chemistry; Spectrum Analysis; Thermodynamics; Titrimetry
• ISSN: 1431-6730
• DOI: 10.1515/BC.2002.187

With respect to the mechanism of chaperonelike activity, we examined the behavior of haptoglobin under heat shock conditions. Secondary structure changes during heat treatment were followed by circular dichroism, Raman and infrared spectroscopy. A model of the haptoglobin tetramer, based on its sequence homology with serine proteases and the CCP modules, has been proposed. Sequence regions responsible for the chaperonelike activity were not fully identical with the region that takes part in formation of the hemoglobinhaptoglobin complex. We can postulate the presence of at least two different chaperonebinding sites on each haptoglobin heavy chain.