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Coupling of ligand ...
Coupling of ligand binding and dimerization of helix-loop-helix peptides: Spectroscopic and sedimentation analyses of calbindin D-9k EF-hands
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- Julenius, Karin (författare)
- Lund University,Lunds universitet,Biofysikalisk kemi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biophysical Chemistry,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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Robblee, James (författare)
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- Thulin, Eva (författare)
- Lund University,Lunds universitet,Biofysikalisk kemi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biophysical Chemistry,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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Finn, Bryan E (författare)
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Fairman, Robert (författare)
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- Linse, Sara (författare)
- Lund University,Lunds universitet,Biofysikalisk kemi,Centrum för Molekylär Proteinvetenskap,Kemiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Biophysical Chemistry,Center for Molecular Protein Science,Department of Chemistry,Departments at LTH,Faculty of Engineering, LTH
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(creator_code:org_t)
- 2002-04-02
- 2002
- Engelska.
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Ingår i: Proteins. - : Wiley. - 0887-3585. ; 47:3, s. 323-333
- Relaterad länk:
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http://dx.doi.org/10...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- Isolated Ca2+-binding EF-hand peptides have a tendency to dimerize. This study is an attempt to account for the coupled equilibria of Ca2+-binding and peptide association for two EF-hands with strikingly different loop sequence and net charge. We have studied each of the two separate EF-hand fragments from calbindin D-9k. A series of Ca2+-titrations at different peptide concentrations were monitored by CD and fluorescence spectroscopy. All data were fitted simultaneously to both a complete model of all possible equilibrium intermediates and a reduced model not including dimerization in the absence of Ca2+. Analytical ultracentrifugation shows that the peptides may occur as monomers or dimers depending on the solution conditions. Our results show strikingly different behavior for the two EF-hands. The fragment containing the N-terminal EF-hand shows a strong tendency to dimerize in the Ca2+-bound state. The average Ca2+-affinity is 3.5 orders of magnitude lower than for the intact protein. We observe a large apparent cooperativity of Ca2+ binding for the overall process from Ca2+-free monomer to fully loaded dimer, showing that a Ca2+-free EF-hand folds upon dimerization to a Ca2+-bound EF-hand, thereby presenting a preformed binding site to the second Ca2+-ion. The C-terminal EF-hand shows a much smaller tendency to dimerize, which may be related to its larger net negative charge. In spite of the differences in dimerization behavior, the Ca2+ affinities of both EF-hand fragments are similar and in the range IgK = 4.6-5.3.
Ämnesord
- NATURVETENSKAP -- Kemi -- Fysikalisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Physical Chemistry (hsv//eng)
Nyckelord
- Molecular
- Models
- Biological
- Ligands
- EF Hand Motifs
- Dimerization
- Cyanogen Bromide : chemistry
- Comparative Study
- Circular Dichroism
- Cattle
- Vitamin D-Dependent : metabolism
- Calcium-Binding Protein
- Vitamin D-Dependent : chemistry
- Calcium : metabolism
- Binding Sites
- Amino Acid Sequence
- Animal
- Molecular Sequence Data
- Peptide Fragments : chemistry
- Protein Binding
- Sequence Alignment
- Spectrometry
- Fluorescence
Publikations- och innehållstyp
- art (ämneskategori)
- ref (ämneskategori)
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