1gzr
From Proteopedia
Human Insulin-like growth factor; ESRF data
Structural highlights
DiseaseIGF1_HUMAN Defects in IGF1 are the cause of insulin-like growth factor I deficiency (IGF1 deficiency) [MIM:608747. IGF1 deficiency is an autosomal recessive disorder characterized by growth retardation, sensorineural deafness and mental retardation. FunctionIGF1_HUMAN The insulin-like growth factors, isolated from plasma, are structurally and functionally related to insulin but have a much higher growth-promoting activity. May be a physiological regulator of [1-14C]-2-deoxy-D-glucose (2DG) transport and glycogen synthesis in osteoblasts. Stimulates glucose transport in rat bone-derived osteoblastic (PyMS) cells and is effective at much lower concentrations than insulin, not only regarding glycogen and DNA synthesis but also with regard to enhancing glucose uptake.[1] 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 PubMedHuman insulin-like growth factors I and II (hIGF-I, hIGF-II) are potent stimulators of cell and growth processes. They display high sequence similarity to both the A and B chains of insulin but contain an additional connecting C-domain, which reflects their secretion without specific packaging or precursor conversion. IGFs also have an extension at the C-terminus known as the D-domain. This paper describes four homologous hIGF-1 structures, obtained from crystals grown in the presence of the detergent SB12, which reveal additional detail in the C- and D-domains. Two different detergent binding modes observed in the crystals may reflect different hIGF-I biological properties such as the interaction with IGF binding proteins and self-aggregation. While the helical core of hIGF-I is very similar to that in insulin, there are distinct differences in the region of hIGF-I corresponding to the insulin B chain C-terminus, residues B25-B30. In hIGF-I, these residues (24-29) and the following C-domain form an extensive loop protruding 20 A from the core, which results in a substantially different conformation for the receptor binding epitope in hIGF-I compared to insulin. One notable feature of the structures presented here is demonstration of peptide-bond cleavage between Ser35 and Arg36 resulting in an apparent gap between residues 35 and 39. The equivalent region of proinsulin is involved in hormone processing demanding a reassessment of the structural integrity of hIGF-I in relation to its biological function. Structural origins of the functional divergence of human insulin-like growth factor-I and insulin.,Brzozowski AM, Dodson EJ, Dodson GG, Murshudov GN, Verma C, Turkenburg JP, de Bree FM, Dauter Z Biochemistry. 2002 Jul 30;41(30):9389-97. PMID:12135360[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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