Agouti structure and function: characterization of a potent alpha-melanocyte stimulating hormone receptor antagonist

Autor: Laura L. Kiefer, Burkhart W, Chris Harris, James S. Nichols, Moyer M, Derril H. Willard, Steven G. Blanchard, Weiel J, Bodnar W, Christine R. Hoffman
Rok vydání: 1995
Předmět:
medicine.medical_specialty
Growth-hormone-releasing hormone receptor
Molecular Sequence Data
Mollusk Venoms
Moths
Biochemistry
Cholinergic Antagonists
Protein Structure
Secondary
Thyroid hormone receptor beta
Mice
Structure-Activity Relationship
Thyrotropin-releasing hormone receptor
Internal medicine
medicine
Animals
Conotoxin
Amino Acid Sequence
Cysteine
Receptors
Pituitary Hormone
Receptor
Protein secondary structure
Cells
Cultured
chemistry.chemical_classification
integumentary system
Sequence Homology
Amino Acid
Chemistry
Circular Dichroism
Proteins
Peptide Fragments
Recombinant Proteins
Amino acid
Endocrinology
alpha-MSH
Agouti Signaling Protein
Intercellular Signaling Peptides and Proteins
Antagonism
Baculoviridae
Oxidation-Reduction
Sequence Analysis
hormones
hormone substitutes
and hormone antagonists
Zdroj: Biochemistry. 34(38)
ISSN: 0006-2960
Popis: The murine agouti gene encodes for a novel 131 amino acid protein. The sequence includes a 22 residue putative secretion signal, an internal basic region, and a C-terminal domain containing 10 cysteines. Agouti has been found to antagonize the binding of certain pro-opiomelanocortin peptides, such as alpha-melanocyte stimulating hormone (alpha-MSH), to the murine melanocortin-1 receptor (MC1-R). We report the purification of a secreted murine agouti to homogeneity by a two-step procedure from baculovirus-infected Trichoplusia ni (T. ni). The protein is glycosylated and exhibits competitive, high-affinity antagonism (Ki = 0.8 nM) versus alpha-MSH in cell-based assays employing B16F10 cells. Association state analysis by analytical ultracentrifugation reveals that agouti exists in a monomer--dimer plus aggregate equilibrium at low micromolar concentrations. Data from secondary structure studies indicate that the protein is highly stable to thermal denaturation. Enzymatic digestion to probe disulfide bond arrangement yielded a discrete C-terminal (Val 83-Cys 131) domain. The isolated highly cysteine-rich C-terminal domain retains alpha-MSH antagonism equipotent with mature agouti. This bioactive domain contains all 10 cysteines which exhibit sequence homology when aligned with several conotoxins.
Databáze: OpenAIRE
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