Bombyxin exhibits an insulin-like response to modification in the N-terminal region of the A chain.
Bombyxin is an insect neurohormone with an insulin-like structure. The N-terminal A chain helix, a region which is considered part of the active site in insulin, is almost identical between the two hormones. Bombyxin analogues with modifications at the N-terminus of the A-chain were synthesized and investigated for their ability to bind to bombyxin-specific receptors. While N-acetylation reduced the affinity to the bombyxin receptor to 18% the removal of glycine (A1) inactivated the hormone completely. Replacement of glycine (A1) by L-amino acids caused a significant loss in activity (11%) while its replacement by D-amino acid resulted in active bombyxin analogues (55%). Comparative CD spectroscopy indicated a change in structure for desGly(A1)bombyxin. Although the insect hormone does not have an insulin-like function it exhibits mammalian insulin-like structural sensitivity for A chain modifications.
Büllesbach
E E
EE
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston 29425, USA. bullesee@musc.edu
D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D007328:Insulin / Q000494:pharmacology*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011487:Protein Conformation; D011956:Receptors, Cell Surface / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D013552:Swine
D007328:Insulin; D009479:Neuropeptides; D011956:Receptors, Cell Surface; C096422:bombyxin receptor; C075028:bombyxins