Structural Study Of A Far-red Fluorescent Protein SmURFP

Fluorescent proteins(FPs)have extremely important application value for biological research.Fluorescent proteins can be used to observe cell activity,label proteins,and carry out related experiments such as proteomics,even for tumor and cancer detection.Among many fluorescent proteins,far-red fluorescent proteins have the advantage of low background imaging and imaging in vivo,therefore,favored by researchers.SmURFP is a far-red fluorescent protein that is a phycobiliprotein by several mutation from TeAPC?.It has high fluorescence intensity,and the excitation and emission wavelength is 642 / 670 nm.SmURFP has important research value and application prospects.We take smURFP as the research object,through the methods of molecular biology and structural biology,to study the crystal structure of smURFP apo-form and biliverdin(BV)binding complex.We constructed clones and expressed a large number of proteins of smURFP in prokaryotic expression system(E.coli).A variety of chromatography methods were used to obtain highly pure smURFP.SmURFP was screened and optimized by crystallography,and we obtained the high-quality and well-diffracted smURFP crystals.We collected the date of 2.1 ? resolution crystal of smURFP by Xray diffraction,and analyzed its three-dimensional structure.The fluorescence intensity test data shows that smURFP and BV can be well combined without cofactors,but no high-quality complex crystals with good diffraction have been obtained yet.We hope to analyze the three-dimensional structure of smURFP apo-form and the BV-binding complex,then reveal the key features of the active center of smURFP at the level of atomic resolution and the mechanism of the interaction between smURFP and the chromophore.As result,we can use these important structural information to further modify smURFP,find and develop more chromophores in the future,and then to obtain fluorescent proteins with higher fluorescence intensity.