title: Insulin analog with additional disulfide bond has increased stability and preserved activity.
abstract: Insulin is a key hormone controlling glucose homeostasis. All known vertebrate insulin analogs have a classical structure with three 100% conserved disulfide bonds that are essential for structural stability and thus the function of insulin. It might be hypothesized that an additional disulfide bond may enhance insulin structural stability which would be highly desirable in a pharmaceutical use. To address this hypothesis, we designed insulin with an additional interchain disulfide bond in positions A10/B4 based on Cα-Cα distances, solvent exposure, and side-chain orientation in human insulin (HI) structure. This insulin analog had increased affinity for the insulin receptor and apparently augmented glucodynamic potency in a normal rat model compared with HI. Addition of the disulfide bond also resulted in a 34.6°C increase in melting temperature and prevented insulin fibril formation under high physical stress even though the C-terminus of the B-chain thought to be directly involved in fibril formation was not modified. Importantly, this analog was capable of forming hexamer upon Zn addition as typical for wild-type insulin and its crystal structure showed only minor deviations from the classical insulin structure. Furthermore, the additional disulfide bond prevented this insulin analog from adopting the R-state conformation and thus showing that the R-state conformation is not a prerequisite for binding to insulin receptor as previously suggested. In summary, this is the first example of an insulin analog featuring a fourth disulfide bond with increased structural stability and retained function.
authors.affiliation: Diabetes Research Unit, Novo Nordisk A/S, Novo Nordisk Park, Måløv DK-2760, Denmark.
authors.forename: Tine N
authors.initials: TN
authors.lastname: Vinther
authors.forename: Mathias
authors.initials: M
authors.lastname: Norrman
authors.forename: Ulla
authors.initials: U
authors.lastname: Ribel
authors.forename: Kasper
authors.initials: K
authors.lastname: Huus
authors.forename: Morten
authors.initials: M
authors.lastname: Schlein
authors.forename: Dorte B
authors.initials: DB
authors.lastname: Steensgaard
authors.forename: Thomas Å
authors.initials: TÅ
authors.lastname: Pedersen
authors.forename: Ingrid
authors.initials: I
authors.lastname: Pettersson
authors.forename: Svend
authors.initials: S
authors.lastname: Ludvigsen
authors.forename: Thomas
authors.initials: T
authors.lastname: Kjeldsen
authors.forename: Knud J
authors.initials: KJ
authors.lastname: Jensen
authors.forename: František
authors.initials: F
authors.lastname: Hubálek
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019943:Amino Acid Substitution; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D001786:Blood Glucose / Q000032:analysis; D002478:Cells, Cultured; D003553:Cystine / Q000737:chemistry* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004355:Drug Stability; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D061386:Insulin, Regular, Human / Q000031:analogs & derivatives* / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D050505:Mutant Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011487:Protein Conformation; D055550:Protein Stability; D051381:Rats; D011922:Rats, Mutant Strains; D017208:Rats, Wistar; D011972:Receptor, Insulin / Q000378:metabolism*; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism
chemical_list: D015703:Antigens, CD; D001786:Blood Glucose; D007004:Hypoglycemic Agents; D061386:Insulin, Regular, Human; D050505:Mutant Proteins; D011994:Recombinant Proteins; C583071:insulin, CysA10-CysB4-desB30-; D003553:Cystine; C435941:INSR protein, human; D011972:Receptor, Insulin; D005947:Glucose; D015032:Zinc