Study of chaperone-like activity of human haptoglobin: conformational changes under heat shock conditions and localization of interaction sites.
With respect to the mechanism of chaperone-like 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 chaperone-like activity were not fully identical with the region that takes part in formation of the hemoglobin-haptoglobin complex. We can postulate the presence of at least two different chaperone-binding sites on each haptoglobin heavy chain.
Ettrich
Rüdiger
R
Institute of Physical Biology, Zámek 136, CZ-37333 Nové Hrady, Czech Republic
Brandt
Wolfgang
W
Kopecký
Vladimír
V
Baumruk
Vladimír
V
Hofbauerová
Katerina
K
Pavlícek
Zdenek
Z
D000595:Amino Acid Sequence; D001665:Binding Sites; D002374:Catalase / Q000737:chemistry; D006242:Haptoglobins / Q000737:chemistry* / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D006454:Hemoglobins / Q000737:chemistry; D006358:Hot Temperature; D006801:Humans; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism; D008969:Molecular Sequence Data; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012997:Solvents / Q000737:chemistry; D013057:Spectrum Analysis; D013816:Thermodynamics; D017186:Titrimetry
D006242:Haptoglobins; D006360:Heat-Shock Proteins; D006454:Hemoglobins; D018832:Molecular Chaperones; D012997:Solvents; D002374:Catalase