Synthesis and conformational analysis of the insulin-like 4 gene product.
Insulin-like 4 (INSL-4) is a protein expressed in the early placenta. Its primary structure is insulin-like with reference to the distribution of cysteine residues and the single chain pro-form. Insulin-like 4 was generated by solid-phase peptide synthesis of the two chains followed by the sequential synthesis of the three disulfide bonds. Two disulfide isomers were produced, one with an insulin-like disulfide bonding pattern and the other with a reversed chain orientation. The CD spectra of the two disulfide isomers were indistinguishable without any features produced by periodic structures. In addition, the hydrodynamic properties of the two isomers were identical which implied a very open structure of the disulfide-bonded two-chain molecules. It appears that insulin-likeness cannot be defined solely on the basis of the primary structure of cDNA.
Büllesbach
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Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425, USA. bullesee@musc.edu
Schwabe
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D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D003545:Cysteine / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004220:Disulfides; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D007536:Isomerism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D011257:Pregnancy Proteins / Q000138:chemical synthesis* / Q000737:chemistry*; D011487:Protein Conformation; D012065:Relaxin / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014466:Ultraviolet Rays
D018076:DNA, Complementary; D004220:Disulfides; D006133:Growth Substances; C101126:INSL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D011257:Pregnancy Proteins; D012065:Relaxin; D003545:Cysteine