Structures of apomyoglobin's various acid-destabilized forms

R. Gilmanshin, M. Gulotta, R. B. Dyer, Robert Callender

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

The structures and the cold and hot melting thermodynamics of the acid- and salt-destabilized states of horse heart apomyoglobin (apoMb), including the E (extended) and various I forms, are studied using probes of tertiary structure (tryptophan fluorescence and FTIR spectroscopy) and secondary structure (far-UV CD and FTIR spectroscopy). These forms likely resemble early structures in the folding of the largely helical protein. Both the I and E forms retain the AGH core whereby the two ends of the protein are tied together with sufficient numbers of tertiary contacts, involving a number of hydrophobic residues, to show cooperative melting. The melting thermodynamics of E and I are distinctly different. E contains no other tertiary structure and probably little other secondary structure apart from the core. The more destabilized E form appears to contain "random" buried runs of polypeptide backbone which convert to α-helix in the I form(s). Most interestingly, E consists not of a single structure but is composed of a heterogeneous mixture of conformations, all showing corelike cooperative melting characteristics, and consisting presumably of varying contacts between the A portion of apomyoglobin and the G - H hairpin. These results bear on the energy landscape and structural features of the early part of apomyoglobin's folding pathway.

Original languageEnglish (US)
Pages (from-to)5127-5136
Number of pages10
JournalBiochemistry
Volume40
Issue number17
StatePublished - May 1 2001

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Freezing
Melting
Acids
Fourier Transform Infrared Spectroscopy
Thermodynamics
Spectroscopy
Fluorescence Spectrometry
Tryptophan
Horses
Conformations
Spectrum Analysis
Proteins
Salts
Fluorescence
Peptides
apomyoglobin

ASJC Scopus subject areas

  • Biochemistry

Cite this

Gilmanshin, R., Gulotta, M., Dyer, R. B., & Callender, R. (2001). Structures of apomyoglobin's various acid-destabilized forms. Biochemistry, 40(17), 5127-5136.

Structures of apomyoglobin's various acid-destabilized forms. / Gilmanshin, R.; Gulotta, M.; Dyer, R. B.; Callender, Robert.

In: Biochemistry, Vol. 40, No. 17, 01.05.2001, p. 5127-5136.

Research output: Contribution to journalArticle

Gilmanshin, R, Gulotta, M, Dyer, RB & Callender, R 2001, 'Structures of apomyoglobin's various acid-destabilized forms', Biochemistry, vol. 40, no. 17, pp. 5127-5136.
Gilmanshin R, Gulotta M, Dyer RB, Callender R. Structures of apomyoglobin's various acid-destabilized forms. Biochemistry. 2001 May 1;40(17):5127-5136.
Gilmanshin, R. ; Gulotta, M. ; Dyer, R. B. ; Callender, Robert. / Structures of apomyoglobin's various acid-destabilized forms. In: Biochemistry. 2001 ; Vol. 40, No. 17. pp. 5127-5136.
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