1B0Q | pdb_00001b0q

DITHIOL ALPHA MELANOTROPIN PEPTIDE CYCLIZED VIA RHENIUM METAL COORDINATION

PDB DOI: https://doi.org/10.2210/pdb1B0Q/pdb

Classification: HORMONE/GROWTH FACTOR
Mutation(s): No

Deposited: 1998-11-12 Released: 1998-11-18
Deposition Author(s): Giblin, M.F., Wang, N., Hoffman, T.J., Jurisson, S.S., Quinn, T.P.

Experimental Data Snapshot

Method: SOLUTION NMR
Conformers Submitted: 1

wwPDB Validation 3D Report Full Report

This is version 1.5 of the entry. See complete history.

Literature

Design and characterization of alpha-melanotropin peptide analogs cyclized through rhenium and technetium metal coordination.

Giblin, M.F., Wang, N., Hoffman, T.J., Jurisson, S.S., Quinn, T.P.

(1998) Proc Natl Acad Sci U S A 95: 12814-12818

PubMed: 9788997 Search on PubMed Search on PubMed Central
DOI: https://doi.org/10.1073/pnas.95.22.12814
Primary Citation Related Structures:
1B0Q

PubMed Abstract:
alpha-Melanocyte stimulating hormone (alpha-MSH) analogs, cyclized through site-specific rhenium (Re) and technetium (Tc) metal coordination, were structurally characterized and analyzed for their abilities to bind alpha-MSH receptors present on melanoma cells and in tumor-bearing mice. Results from receptor-binding assays conducted with B16 F1 murine melanoma cells indicated that receptor-binding affinity was reduced to approximately 1% of its original levels after Re incorporation into the cyclic Cys4,10, D-Phe7-alpha-MSH4-13 analog. Structural analysis of the Re-peptide complex showed that the disulfide bond of the original peptide was replaced by thiolate-metal-thiolate cyclization. A comparison of the metal-bound and metal-free structures indicated that metal complexation dramatically altered the structure of the receptor-binding core sequence. Redesign of the metal binding site resulted in a second-generation Re-peptide complex (ReCCMSH) that displayed a receptor-binding affinity of 2.9 nM, 25-fold higher than the initial Re-alpha-MSH analog. Characterization of the second-generation Re-peptide complex indicated that the peptide was still cyclized through Re coordination, but the structure of the receptor-binding sequence was no longer constrained. The corresponding 99mTc- and 188ReCCMSH complexes were synthesized and shown to be stable in phosphate-buffered saline and to challenges from diethylenetriaminepentaacetic acid (DTPA) and free cysteine. In vivo, the 99mTcCCMSH complex exhibited significant tumor uptake and retention and was effective in imaging melanoma in a murine-tumor model system. Cyclization of alpha-MSH analogs via 99mTc and 188Re yields chemically stable and biologically active molecules with potential melanoma-imaging and therapeutic properties.

Organizational Affiliation

Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.

Macromolecule Content

Total Structure Weight: 1.52 kDa
Atom Count: 95
Modeled Residue Count: 12
Deposited Residue Count: 12
Unique protein chains: 1

Macromolecules

Find similar proteins by: Sequence | 3D Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
PROTEIN (CYCLIC ALPHA MELANOCYTE STIMULATING HORMONE)	A	12	N/A	Mutation(s): 0

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram	3D Interactions
RE Query on RE Download:Ideal Coordinates CCD File SDF format, chain B [auth A] MOL2 format, chain B [auth A] mmCIF format, chain B [auth A]	B [auth A]	RHENIUM Re WUAPFZMCVAUBPE-UHFFFAOYSA-N		Interactions Focus chain B [auth A]