Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea: A molten globule when deprived of Ca2+

Helena Aitio, Tero Laakso, Tero Pihlajamaa, Mika Torkkeli, Ilkka Kilpeläinen, Torbjörn Drakenberg, Ritva Serimaa, Arto Annila

Research output: Contribution to journalArticleScientificpeer-review

18 Citations (Scopus)

Abstract

Calerythrin, a four-EF-hand calcium-binding protein from Saccharopolyspora erythraea, exists in an equilibrium between ordered and less ordered states with slow exchange kinetics when deprived of Ca2+ and at low temperatures, as observed by NMR. As the temperature is raised, signal dispersion in NMR spectra reduces, and intensity of near-UV CD bands decreases. Yet far-UV CD spectra indicate only a small decrease in the amount of secondary structure, and SAXS data show that no significant change occurs in the overall size and shape of the protein. Thus, at elevated temperatures, the equilibrium is shifted toward a state with characteristics of a molten globule. The fully structured state is reached by Ca2+-titration. Calcium first binds cooperatively to the C-terminal sites 3 and 4 and then to the N-terminal site 1, which is paired with an atypical, nonbinding site 2. EF-hand 2 still folds together with the C-terminal half of the protein, as deduced from the order of appearance of backbone amide cross peaks in the NMR spectra of partially Ca2+-saturated states.
Original languageEnglish
Pages (from-to)74-82
Number of pages9
JournalProtein Science
Volume10
Issue number1
DOIs
Publication statusPublished - 2001
MoE publication typeA1 Journal article-refereed

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EF Hand Motifs
Protein S
Molten materials
Nuclear magnetic resonance
Temperature
Saccharopolyspora
Peptide Elongation Factor 2
Calcium-Binding Proteins
Titration
Amides
Proteins
Calcium
Kinetics

Cite this

Aitio, Helena ; Laakso, Tero ; Pihlajamaa, Tero ; Torkkeli, Mika ; Kilpeläinen, Ilkka ; Drakenberg, Torbjörn ; Serimaa, Ritva ; Annila, Arto. / Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea : A molten globule when deprived of Ca2+. In: Protein Science. 2001 ; Vol. 10, No. 1. pp. 74-82.
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title = "Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea: A molten globule when deprived of Ca2+",
abstract = "Calerythrin, a four-EF-hand calcium-binding protein from Saccharopolyspora erythraea, exists in an equilibrium between ordered and less ordered states with slow exchange kinetics when deprived of Ca2+ and at low temperatures, as observed by NMR. As the temperature is raised, signal dispersion in NMR spectra reduces, and intensity of near-UV CD bands decreases. Yet far-UV CD spectra indicate only a small decrease in the amount of secondary structure, and SAXS data show that no significant change occurs in the overall size and shape of the protein. Thus, at elevated temperatures, the equilibrium is shifted toward a state with characteristics of a molten globule. The fully structured state is reached by Ca2+-titration. Calcium first binds cooperatively to the C-terminal sites 3 and 4 and then to the N-terminal site 1, which is paired with an atypical, nonbinding site 2. EF-hand 2 still folds together with the C-terminal half of the protein, as deduced from the order of appearance of backbone amide cross peaks in the NMR spectra of partially Ca2+-saturated states.",
author = "Helena Aitio and Tero Laakso and Tero Pihlajamaa and Mika Torkkeli and Ilkka Kilpel{\"a}inen and Torbj{\"o}rn Drakenberg and Ritva Serimaa and Arto Annila",
year = "2001",
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Aitio, H, Laakso, T, Pihlajamaa, T, Torkkeli, M, Kilpeläinen, I, Drakenberg, T, Serimaa, R & Annila, A 2001, 'Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea: A molten globule when deprived of Ca2+', Protein Science, vol. 10, no. 1, pp. 74-82. https://doi.org/10.1110/ps.31201

Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea : A molten globule when deprived of Ca2+. / Aitio, Helena; Laakso, Tero; Pihlajamaa, Tero; Torkkeli, Mika; Kilpeläinen, Ilkka; Drakenberg, Torbjörn; Serimaa, Ritva; Annila, Arto.

In: Protein Science, Vol. 10, No. 1, 2001, p. 74-82.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Characterization of apo and partially saturated states of calerythrin, an EF-hand protein from S. erythraea

T2 - A molten globule when deprived of Ca2+

AU - Aitio, Helena

AU - Laakso, Tero

AU - Pihlajamaa, Tero

AU - Torkkeli, Mika

AU - Kilpeläinen, Ilkka

AU - Drakenberg, Torbjörn

AU - Serimaa, Ritva

AU - Annila, Arto

PY - 2001

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N2 - Calerythrin, a four-EF-hand calcium-binding protein from Saccharopolyspora erythraea, exists in an equilibrium between ordered and less ordered states with slow exchange kinetics when deprived of Ca2+ and at low temperatures, as observed by NMR. As the temperature is raised, signal dispersion in NMR spectra reduces, and intensity of near-UV CD bands decreases. Yet far-UV CD spectra indicate only a small decrease in the amount of secondary structure, and SAXS data show that no significant change occurs in the overall size and shape of the protein. Thus, at elevated temperatures, the equilibrium is shifted toward a state with characteristics of a molten globule. The fully structured state is reached by Ca2+-titration. Calcium first binds cooperatively to the C-terminal sites 3 and 4 and then to the N-terminal site 1, which is paired with an atypical, nonbinding site 2. EF-hand 2 still folds together with the C-terminal half of the protein, as deduced from the order of appearance of backbone amide cross peaks in the NMR spectra of partially Ca2+-saturated states.

AB - Calerythrin, a four-EF-hand calcium-binding protein from Saccharopolyspora erythraea, exists in an equilibrium between ordered and less ordered states with slow exchange kinetics when deprived of Ca2+ and at low temperatures, as observed by NMR. As the temperature is raised, signal dispersion in NMR spectra reduces, and intensity of near-UV CD bands decreases. Yet far-UV CD spectra indicate only a small decrease in the amount of secondary structure, and SAXS data show that no significant change occurs in the overall size and shape of the protein. Thus, at elevated temperatures, the equilibrium is shifted toward a state with characteristics of a molten globule. The fully structured state is reached by Ca2+-titration. Calcium first binds cooperatively to the C-terminal sites 3 and 4 and then to the N-terminal site 1, which is paired with an atypical, nonbinding site 2. EF-hand 2 still folds together with the C-terminal half of the protein, as deduced from the order of appearance of backbone amide cross peaks in the NMR spectra of partially Ca2+-saturated states.

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