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PDBsum entry 1fb9
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Signaling protein
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PDB id
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1fb9
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Contents |
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* Residue conservation analysis
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References listed in PDB file
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Key reference
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Title
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Solution structure and biological activity of recombinant salmon calcitonin s-Sulfonated analog.
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Authors
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Y.Wang,
H.Dou,
C.Cao,
N.Zhang,
J.Ma,
J.Mao,
H.Wu.
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Ref.
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Biochem Biophys Res Commun, 2003,
306,
582-589.
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PubMed id
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Abstract
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Salmon calcitonin S-sulfonated analog (abbreviated as [S-SO(3)(-)]rsCT) was
prepared by introducing two sulfonic groups into the side chains of Cys1 and
Cys7 of recombinant salmon calcitonin. The hypocalcemic potency of this
open-chain analog is 5500IU/mg, which is about 30% higher than that (4500IU/mg)
of the wild type. The solution conformation of [S-SO(3)(-)]rsCT was studied in
aqueous trifluoroethanol solution by CD, 2D-NMR spectroscopy, and distance
geometry calculations. In the mixture of 60% TFE and 40% water, the peptide
assumes an amphipathic alpha-helix in the region of residues 4-22, which is one
turn longer than that of the native sCT. The structural feature analysis of the
peptide revealed the presence of hydrophobic surface composed of five
hydrophobic side chains of residues Leu4, Leu9, Leu12, Leu16, and Leu19, and a
network of salt-bridges that consisted of a tetrad of oppositely charged side
chains (Cys7-SO(3)(-)-Lys11(+)-Glu15(-)-Lys18(+)). The multiple salt bridges
resulted in the stabilization of the longer amphipathic alpha-helix. Meanwhile,
the higher hypocalcemic potency of the peptide could be attributed to the array
of hydrophobic side chains of five leucine residues of the amphipathic
alpha-helix.
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