Unfolding Of C-reactive Protein In Urea And Its Bioinformatics Analysis

C-reactive protein(CRP) is a classic acute phase protein, which exists at least two isoforms, pCRP or nCRP, the pentameric one, and mCRP, the modified or monomeric one. The conformational change of the two isoforms contributes to the pleiotropic effects of CRP. pCRP was denatured by urea-EDTA in different time to show the process of CRP unfolding. Thus, we identified two CRP intermediates, CRPi and mCRPi. Finally, a more detailed process of CRP unfolding was described. In particular, CRPi is a new isoform expressing1D6epitopes while losing the pentameric conformation. The identification of CRPi and mCRPi and the description of the CRP unfolding progress can help us to know better of the mechanism of the conformational change of different CRP isoforms. And also, it may explain the pleiotropic effects of CRP. Besides, we compared CRP with SAP, also a plasma protein of the pentraxin, in the primary sequence, and we also made an analysis of sequence conversation among their species. Furthermore, we compared the structure of CRP subunit with some predicted models of mCRP mutants. Thus, we found some important elements, such as Ca-binding loop(136-150), Cys-Cys, Ser45Thr46, LNWRA(185-189), strand G(80-85) and the signal peptide of CRP, which may affect the folding and assembly of CRP. Eventually, we did complete alignment with the transcriptional regulation elements of CRP, SAP and SAA, also an acute phase protein. We also made an analysis of elements conversation among their species. We found some important elements, p50*p50, C/EBP and CREBH, which may strongly regulate the acute phase expression of CRP. The Bioinformatics analysis showed a target for researchers in the folding of CRP and regulation of acute phase expression.