Purchase this article with an account.
Marie Vestergaard Lukassen, Carsten Scavenius, Ida B Thøgersen, Jan J Enghild; The disulphide bond pattern of TGFBIp. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4911.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Transforming growth factor beta-induced protein (TGFBIp) is the second most abundant protein in the human cornea, but its structure and function are largely unknown. A previous study has shown that TGFBIp is bound to collagen type XII in the cornea through a reducible bond. This study aims to solve the disulphide pattern of TGFBIp in order to identify the free cysteine that binds to collagen type XII. This structural information will shed light on the role of TGFBIp in the healthy cornea as well as in TGFBIp related corneal dystrophies.
Purified recombinant TGFBIp was processed by extensive proteolysis and the generated peptides were separated by liquid chromatography. Peaks with cysteine-containing peptides were identified by mass spectrometry and disulphide bridges were confirmed by N-terminal sequencing and mass spectrometry analysis.
TGFBIp contains 11 cysteine residues. Six of these are located in the N-terminal EMI domain, one in the FAS1-1 domain, two in the FAS1-2 domain, and two in the FAS1-3 domain. We have identified five disulphide bridges, which are both intra- and inter-domain. Additionally one cysteine residue was found not to participate in any disulphide bridges.
In this study we have solved the disulphide bond pattern of TGFBIp and one free cysteine residue was identified. We suggest the bond to collagen type XII is through this free cysteine residue. The next step will be to characterize the binding between TGFBIp and collagen XII. The soluble fraction of TGFBIp have been proposed to be the one that aggregates in corneal dystrophies, hence the bond to collagen type XII is suggested to be involved in the molecular pathogenesis of the disease.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
This PDF is available to Subscribers Only