Phenol-Promoted Structural Transformation of Insulin in Solution

Wollmer, Axel; Rannefeld, Barbara; Johansen, B R; Hejnaes, K R; Balschmidt, Per; Hansen, Frede

doi:10.1515/bchm3.1987.368.2.903

Cited by 71 publications

(56 citation statements)

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“…For example, such a difference is evident by the divergent near-and far-UV CD spectra for LysPro and insulin under identical conditions ( Fig. 4A and B; Wollmer et al, 1987). Further CD results examine these differences in more detail and reveal the noncoincident titration profiles for both zinc-insulin and zinc-LysPro in various amounts of phenolic ligand as depicted in Figure 5A and B.…”

Section: Conserving the Rapid Time-action Of Lyspromentioning

confidence: 92%

“…The increase in negative ellipticity at 224 nm seen as phenol and m-cresol are added is consistent with an increase in a-helix. For insulin, phenolic ligands induce the T6-state hexamer to convert to an &-state, whereby the eight N-terminal residues of the B-chain convert from an extended conformation to an cy-helix (Renscheidt et al, 1984;Wollmer et al, 1987;Brader & Dunn, 1991). The ligand-induced change in ellipticity for LysPro, although smaller in Cobalt ion concentrations were used to determine extinction coefficients.…”

Section: CDmentioning

confidence: 99%

“…The human insulin hexamer complex formed in the presence of metal ions such as zinc or cobalt and the subsequent conformational changes that occur upon addition of phenolic ligands have been well documented (Bentley et al, 1976;Renscheidt et al, 1984;Wollmer et al, 1987;Baker et al, 1988;Derewenda et al, 1989;Roy et al, 1989;Thomas & Wollmer, 1989;Kriiger et al, 1990;Brader & Dunn, 1991;Brader et al, 1991;Smith & Dodson, 1992). For human insulin, the presence of zinc promotes association to the hexameric state in what is referred to as the Testate conformation, where two zinc ions are bound by the HisB" residues of each subunit.…”

Section: Stability and Conformution Of Ligand-bound Lyspro Hexamermentioning

confidence: 99%

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Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex

et al. 1996

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The rate-limiting step for the absorption of insulin solutions after subcutaneous injection is considered to be the dissociation of self-associated hexamers to monomers. To accelerate this absorption process, insulin analogues have been designed that possess full biological activity and yet have greatly diminished tendencies to self-associate. Sedimentation velocity and static light scattering results show that the presence of zinc and phenolic ligands (m-cresol and/or phenol) cause one such insulin analogue, L y~~~~P r o~~~-h u m a n insulin (LysPro), to associate into a hexameric complex. Most importantly, this ligand-bound hexamer retains its rapid-acting pharmacokinetics and pharmacodynamics. The dissociation of the stabilized hexameric analogue has been studied in vitro using static light scattering as well as in vivo using a female pig pharmacodynamic model. Retention of rapid time-action is hypothesized to be due to altered subunit packing within the hexamer. Evidence for modified monomer-monomer interactions has been observed in the X-ray crystal structure of a zinc LysPro hexamer (Ciszak E et al., 1995, Structure 3:615-622). The solution state behavior of LysPro, reported here, has been interpreted with respect to the crystal structure results. In addition, the phenolic ligand binding differences between LysPro and insulin have been compared using isothermal titrating calorimetry and visible absorption spectroscopy of cobalt-containing hexamers. These studies establish that rapid-acting insulin analogues of this type can be stabilized in solution via the formation of hexamer complexes with altered dissociation properties.

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Section: Conserving the Rapid Time-action Of Lyspromentioning

confidence: 92%

Section: CDmentioning

confidence: 99%

Section: Stability and Conformution Of Ligand-bound Lyspro Hexamermentioning

confidence: 99%

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Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex

et al. 1996

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“…Transformation with SCN°T he time course of the transformation on Co(II)2lns 6 by SCN® ions was recorded as a function of SCN 0 concentration. The curve for a molar ratio SCN®: insulin monomer = 350 : 1 is depicted as an example in Fig. l.This excess is known from our titration studies to produce the full effect SCN® is capable of, which corresponds to theT 6 -^T 3 R 3 transition [12] .The curve can be fitted by a single exponential, the residuals are shown in the inset.…”

Section: Resultsmentioning

confidence: 99%

Kinetic Measurements of T→ R Structural Transitions in Insulin

Karatas¹,

Krüger²,

Wollmer³

1991

Biological Chemistry Hoppe-Seyler

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The T 6^T3 R 3 and T 3 R 3 -» R 6 -structural transitions of cobalt insulin hexamers as induced by SCN® ions or m-cresol were studied in stopped-flow experiments using the absorption in the visible for monitoring their time course. TheT 6 -»T 3 R 3 transition induced by either SCN® or limited concentrations of m-cresol is mono-exponential with a rate constant of 0.1 s" 1 and 0.4s" 1 , respectively. A mono-exponential time course is also encountered for the m-cresol-inducedT 3 R 3^ R 6 transition when starting from theT 3 R 3 state preestablished by either SCN° or m-cresol. The corresponding rate constants are 1.3 s" 1 and 0.49 s" 1 , respectively. If m-cresol is used beyond the concentration range where transformation is limited to one trimer, two exponentials are required for fitting the time course. The second exponential corresponds to theT 3 R 3 -> RÖ step with a concentration-independent rate constant of 0.4 s -1 .The rate constant for the fasterT 6 -»T 3 R 3 transition, however, increases with increasing excess of m-cresol. Kinetische Untersuchungen von -Strukturübergängen im InsulinZusammenfassung: Die Strukturumwandlung des hexameren Kobalt-Insulins vonT 6 nachT 3 R 3 undT 3 R 3 nach RO durch SCN®-Ionen bzw. m-Kresol wurde stopped-flow-kinetisch untersucht. Als Indikator diente die Kobalt-Absorption im sichtbaren Bereich. DerT 6 -H»T 3 R 3 -Übergang zeigt einen mono-exponentiellen Zeitverlauf, bei Induktion durch SCN e -Ionen wie auch durch begrenzte m-Kresol-Konzentrationen, mit Geschwindigkeitskonstanten von 0.1 s" 1 bzw. 0.4 s" 1 . Monoexponentiell ist auch der Zeit verlauf desT 3 R 3 -»Re-Überganges, einerlei ob derT 3 R 3 -Ausgangszustand vorher mit SCN 0 -Ionen oder mKresol etabliert wird. Die Geschwindigkeitskonstante beträgt 1.3 s" 1 bzw. 0.49 s' 1 . Wird mehr m-Kresol verwendet als zur Halbumwandlung erforderlich ist, so läßt sich der Zeitverlauf der Umwandlung nur mit 2 e-Funktionen anpassen. Die zweite entspricht demT 3 R 3 ->R 6 -Übergang mit einer konzentrationsunabhängigen Geschwindigkeitskonstante von 0.4 s" 1 . Die Geschwindigkeitskonstante des schnelleren T 6^» T 3 R 3 -Überganges hingegen steigt mit steigendem Überschuß an m-Kresol.

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“…The amino terminus, when N-acetylated, shows reduced receptor binding by 30 %, indicating that a free positively charged amino terminus is critical for receptor binding [20]. Deleting Gly1 reduces activity by 15 %, indicating that the salt bridge formed between Gly1 and the carboxy terminus of the B chain is important for correct positioning of the peptide [6].…”

Section: Insulin Structure-function Relationshipsmentioning

confidence: 99%

Regulation of Insulin Synthesis and Secretion and Pancreatic Beta-Cell Dysfunction in Diabetes

Fu¹,

Gilbert²,

Liu³

2012

CDR

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Pancreatic β-cell dysfunction plays an important role in the pathogenesis of both type 1 and type 2 diabetes. Insulin, which is produced in β-cells, is a critical regulator of metabolism. Insulin is synthesized as preproinsulin and processed to proinsulin. Proinsulin is then converted to insulin and C-peptide and stored in secretary granules awaiting release on demand. Insulin synthesis is regulated at both the transcriptional and translational level. The cis-acting sequences within the 5′ flanking region and trans-activators including paired box gene 6 (PAX6), pancreatic and duodenal homeobox-1(PDX-1), MafA, and B-2/Neurogenic differentiation 1 (NeuroD1) regulate insulin transcription, while the stability of preproinsulin mRNA and its untranslated regions control protein translation. Insulin secretion involves a sequence of events in β-cells that lead to fusion of secretory granules with the plasma membrane. Insulin is secreted primarily in response to glucose, while other nutrients such as free fatty acids and amino acids can augment glucose-induced insulin secretion. In addition, various hormones, such as melatonin, estrogen, leptin, growth hormone, and glucagon like peptide-1 also regulate insulin secretion. Thus, the β-cell is a metabolic hub in the body, connecting nutrient metabolism and the endocrine system. Although an increase in intracellular [Ca 2+ ] is the primary insulin secretary signal, cAMP signaling-dependent mechanisms are also critical in the regulation of insulin secretion. This article reviews current knowledge on how β-cells synthesize and secrete insulin. In addition, this review presents evidence that genetic and environmental factors can lead to hyperglycemia, dyslipidemia, inflammation, and autoimmunity, resulting in β-cell dysfunction, thereby triggering the pathogenesis of diabetes. Keywords β-cell; diabetes; glucose; hormones; insulin secretion; insulin synthesis INSULIN Insulin structureThe crystal structure of insulin is well documented as well as the structural features that confer receptor binding affinity and activity. This has been extensively reviewed and readers are encouraged to visit [1] and [2] for excellent discussions on insulin structure and structure-activity relationships. As discussed in this review, insulin receptor downstream signaling intersects with the signaling pathways of other growth factors, including IGF1 and Correspondence: Dongmin Liu, Ph.D, Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA 24061, Tel: 540-231-3402, Fax: 540-231-3916, doliu@vt.edu. CONFLICTS OF INTERESTThe authors declare that they have no conflict of interest. NIH Public Access Author ManuscriptCurr Diabetes Rev. Author manuscript; available in PMC 2014 February 25. Published in final edited form as:Curr Diabetes Rev. 2013 January 1; 9(1): 25-53. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript IGF2 [3]. This demonstrates the importance of identifying receptor ligand agonists as potential insulin-mimetic therapeutic agent...

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Phenol-Promoted Structural Transformation of Insulin in Solution

Cited by 71 publications

References 2 publications

Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex

Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex

Kinetic Measurements of T→ R Structural Transitions in Insulin

Regulation of Insulin Synthesis and Secretion and Pancreatic Beta-Cell Dysfunction in Diabetes

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Phenol-Promoted Structural Transformation of Insulin in Solution

Cited by 71 publications

References 2 publications

Physicochemical basis for the rapid time‐action of LysB28ProB29‐insulin: Dissociation of a protein‐ligand complex

Physicochemical basis for the rapid time‐action of LysB28ProB29‐insulin: Dissociation of a protein‐ligand complex

Kinetic Measurements of T→ R Structural Transitions in Insulin

Regulation of Insulin Synthesis and Secretion and Pancreatic Beta-Cell Dysfunction in Diabetes

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Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex

Physicochemical basis for the rapid time‐action of Lys^B28Pro^B29‐insulin: Dissociation of a protein‐ligand complex