1tgr

From Proteopedia

Crystal Structure of mini-IGF-1(2)

Structural highlights

1tgr is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 1.42Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Disease

IGF1_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.

Function

IGF1_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 PubMed

Insulin and insulin-like growth factor 1 (IGF-1) share a homologous sequence, a similar three-dimensional structure and weakly overlapping biological activity, but IGF-1 folds into two thermodynamically stable disulfide isomers, while insulin folds into one unique stable tertiary structure. This is a very interesting phenomenon in which one amino acid sequence encodes two three-dimensional structures, and its molecular mechanism has remained unclear for a long time. In this study, the crystal structure of mini-IGF-1(2), a disulfide isomer of an artificial analog of IGF-1, was solved by the SAD/SIRAS method using our in-house X-ray source. Evidence was found in the structure showing that the intra-A-chain/domain disulfide bond of some molecules was broken; thus, it was proposed that disulfide isomerization begins with the breakdown of this disulfide bond. Furthermore, based on the structural comparison of IGF-1 and insulin, a new assumption was made that in insulin the several hydrogen bonds formed between the N-terminal region of the B-chain and the intra-A-chain disulfide region of the A-chain are the main reason for the stability of the intra-A-chain disulfide bond and for the prevention of disulfide isomerization, while Phe B1 and His B5 are very important for the formation of these hydrogen bonds. Moreover, the receptor binding property of IGF-1 was analyzed in detail based on the structural comparison of mini-IGF-1(2), native IGF-1, and small mini-IGF-1.

1.42A crystal structure of mini-IGF-1(2): an analysis of the disulfide isomerization property and receptor binding property of IGF-1 based on the three-dimensional structure.,Yun CH, Tang YH, Feng YM, An XM, Chang WR, Liang DC Biochem Biophys Res Commun. 2005 Jan 7;326(1):52-9. PMID:15567151^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Zoidis E, Ghirlanda-Keller C, Schmid C. Stimulation of glucose transport in osteoblastic cells by parathyroid hormone and insulin-like growth factor I. Mol Cell Biochem. 2011 Feb;348(1-2):33-42. doi: 10.1007/s11010-010-0634-z. Epub, 2010 Nov 13. PMID:21076856 doi:10.1007/s11010-010-0634-z
↑ Yun CH, Tang YH, Feng YM, An XM, Chang WR, Liang DC. 1.42A crystal structure of mini-IGF-1(2): an analysis of the disulfide isomerization property and receptor binding property of IGF-1 based on the three-dimensional structure. Biochem Biophys Res Commun. 2005 Jan 7;326(1):52-9. PMID:15567151 doi:10.1016/j.bbrc.2004.10.203