PDBsum entry 2glg

Hormone/growth factor

PDB id: 2glg

Contents

Protein chain

33 a.a. *

* Residue conservation analysis

PDB id:

2glg

Name:

Hormone/growth factor

Title:

Nmr structure of the [l23,a24]-sct mutant

Structure:

Calcitonin-1. Chain: a. Engineered: yes. Mutation: yes

Source:

Synthetic: yes. Other_details: synthesis on polyoxyethylenepolystyrene graft resin

NMR struc:

100 models

Authors:

G.Andreotti,B.Lopez-Mendez,P.Amodeo,M.A.Morelli,H.Nakamuta,A.Motta

Key ref:

G.Andreotti et al. (2006). Structural determinants of salmon calcitonin bioactivity: the role of the Leu-based amphipathic alpha-helix. J Biol Chem, 281, 24193-24203. PubMed id: 16766525 DOI: 10.1074/jbc.M603528200

Date:

04-Apr-06 Release date: 20-Jun-06

Protein chain

P01263  (CALC1_ONCKE) -  Calcitonin-1 from Oncorhynchus keta

Seq: 136 a.a.

Struc: 33 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1074/jbc.M603528200

J Biol Chem 281:24193-24203 (2006)

PubMed id: 16766525

Structural determinants of salmon calcitonin bioactivity: the role of the Leu-based amphipathic alpha-helix.

G.Andreotti, B.L.Méndez, P.Amodeo, M.A.Morelli, H.Nakamuta, A.Motta.

ABSTRACT

Salmon calcitonin (sCT) forms an amphipathic helix in the region 9-19, with the C-terminal decapeptide interacting with the helix (Amodeo, P., Motta, A., Strazzullo, G., Castiglione Morelli, M. A. (1999) J. Biomol. NMR 13, 161-174). To uncover the structural requirements for the hormone bioactivity, we investigated several sCT analogs. They were designed so as to alter the length of the central helix by removal and/or replacement of flanking residues and by selectively mutating or deleting residues inside the helix. The helix content was assessed by circular dichroism and NMR spectroscopies; the receptor binding affinity in human breast cancer cell line T 47D and the in vivo hypocalcemic activity were also evaluated. In particular, by NMR spectroscopy and molecular dynamics calculations we studied Leu(23),Ala(24)-sCT in which Pro(23) and Arg(24) were replaced by helix inducing residues. Compared with sCT, it assumes a longer amphipathic alpha-helix, with decreased binding affinity and one-fifth of the hypocalcemic activity, therefore supporting the idea of a relationship between a definite helix length and bioactivity. From the analysis of other sCT mutants, we inferred that the correct helix length is located in the 9-19 region and requires long range interactions and the presence of specific regions of residues within the sequence for high binding affinity and hypocalcemic activity. Taken together, the structural and biological data identify well defined structural parameters of the helix for sCT bioactivity.

Selected figure(s)

Figure 3.
FIGURE 3. A, stereo view of the backbone superposition of the 100 Leu^23,Ala^24-sCT periodically sampled structures along the 1000-ps unrestrained MD. Structures were superimposed for pairwise minimum r.m.s. deviation of the N, C , and C atoms of residues 4–28. B, stereo view of Leu^23,Ala^24-sCT structure showing the amphipathic property of the -helix; hydrophobic residues, mainly leucine, are on the left side, whereas hydrophilic amino acids are on the right side. Hydrogen bonds along the backbone and in the N and C terminus helix cap motifs are represented as discontinuous lines.

Figure 5.
FIGURE 5. -Helical content of CT mutants in SDS as obtained from the NMR qualitative pattern recognition approach (see "Results"). Horizontal bars symbolize the helix, a square represents a substitution, whereas a cross indicates a deletion within the sequence. Mutants are labeled as in Tables 1 and 2. The region corresponding to the putative biologically relevant helix is shaded.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2006, 281, 24193-24203) copyright 2006.

Figures were selected by an automated process.