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THE STRUCTURE OF A COMPLEX OF HEXAMERIC INSULIN AND 4'-HYDROXYACETANILIDE
Structural highlights
DiseaseINS_HUMAN Defects in INS are the cause of familial hyperproinsulinemia (FHPRI) [MIM:176730.[1] [2] [3] [4] Defects in INS are a cause of diabetes mellitus insulin-dependent type 2 (IDDM2) [MIM:125852. IDDM2 is a multifactorial disorder of glucose homeostasis that is characterized by susceptibility to ketoacidosis in the absence of insulin therapy. Clinical fetaures are polydipsia, polyphagia and polyuria which result from hyperglycemia-induced osmotic diuresis and secondary thirst. These derangements result in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.[5] Defects in INS are a cause of diabetes mellitus permanent neonatal (PNDM) [MIM:606176. PNDM is a rare form of diabetes distinct from childhood-onset autoimmune diabetes mellitus type 1. It is characterized by insulin-requiring hyperglycemia that is diagnosed within the first months of life. Permanent neonatal diabetes requires lifelong therapy.[6] [7] Defects in INS are a cause of maturity-onset diabetes of the young type 10 (MODY10) [MIM:613370. MODY10 is a form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.[8] [9] [10] FunctionINS_HUMAN Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedX-ray crystallographic studies have been carried out on human insulin crystals grown in the presence of 4'-hydroxyacetanilide (Tylenol) and show that this nontoxic phenolic derivative can induce the T-->R transition, producing a T3R3 hexamer. Two different crystals, grown under different conditions, are rhombohedral, space group R3, with cell constants a = 81.11, c = 37.97 and a = 80.88, c = 37.60 A. The T3R3 hexamer is symmetric, resulting from the presence of a crystallographic threefold axis, and the asymmetric unit consists of a TR dimer. Data to a resolution of 1.9 A were measured on a crystal from each of the two crystallizations and the structures have been refined to residuals of 0.168 and 0.173. The guest molecule is bound by the R-state monomer through the formation of two hydrogen bonds from the hydroxy group of Tylenol to the carbonyl oxygen and the nitrogen of A6 Cys and A11 Cys, respectively. Due to steric constraints of the phenolic binding site, the acetamide group of Tylenol is rotated approximately 50 degrees out of the plane of the phenyl group and the methyl group is cis; no hydrogen bonds exist between the acetamide group and the hexamer. Although the zinc ion, which is bound to the R-state trimer, has tetrahedral coordination in both structures, the T-state zinc is observed to have octahedral coordination in one structure but tetrahedral coordination in the other. The side chain of A10 Ile in the R-state monomer adopts a high-energy conformation as a result of close contact to a residue in an adjacent dimer and may explain in part the differences between therapeutic preparations of beef insulin, for which A10 is a Val residue, and human insulin. The structure of a complex of hexameric insulin and 4'-hydroxyacetanilide.,Smith GD, Ciszak E Proc Natl Acad Sci U S A. 1994 Sep 13;91(19):8851-5. PMID:8090735[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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