Crystal structure of the cyan fluorescent protein Cerulean‐S175G. Issue 7 (1st July 2016)

• Record Type: Journal Article
• Authors: Park, Sang-wook; Kang, Sunghyun; Yoon, Tae-Sung
• Is Part Of: Acta crystallographica. Volume 72:Issue 7(2016:Jul.)
• Page Start: 516
• Page End: 522
• Publication Date: 2016-07-01
• Subjects: Cerulean‐S175G -- enhanced cyan fluorescent protein -- fluorophores -- fluorescence resonance energy transfer -- fluorescence lifetime imaging microscopy; Crystallography -- Periodicals; Crystals -- Periodicals; 548
• DOI: 10.1107/S2053230X16008311
• Languages: English
• ISSNs: 2053-230X

Abstract

Abstract : The crystal structure of Cerulean‐S175G was compared with those of Cerulean and SCFP3A, which are notable variants of enhanced cyan fluorescent protein (ECFP). A detailed comparison of the three structures revealed that the notable conformational changes of ECFP variants can be understood mainly in terms of the interaction between the Trp66 residue of the chromophore and residues 145–148 of β‐strand 7. Abstract : Enhanced cyan fluorescent protein (ECFP) was derived from Aequorea victoria green fluorescent protein ( av GFP), notably with S65T/Y66W mutations. Its chromophore consists of a tripeptide comprised of Thr65, Trp66 and Gly67 (TWG) residues, while that of av GFP consists of a Ser65, Tyr66 and Gly67 (SYG) tripeptide. Cerulean and SCFP3A were derived from ECFP‐S72A/H148D (a double mutation) with additional Y145A and S175G mutations, respectively, while Cerulean‐S175G has both mutations (Y145A and S175G). The crystal structures of these ECFP variants at neutral pH were reported to adopt two distinct major conformations called ECFP and Cerulean . In this study, Cerulean‐S175G was revealed to adopt only the Cerulean conformation, while Cerulean has been reported to adopt both the ECFP and the Cerulean conformations in its crystal structures. Sharing the same S175G mutation with SCFP3A, Cerulean‐S175G showed a slightly increased quantum yield, like SCFP3A, but did not adopt the ECFP conformation adopted by SCFP3A. Detailed comparison of Cerulean‐S175G and other ECFP variants revealed that the notable conformational changes in ECFP variants can be understood mainly in terms of the interaction between the Trp66 residue of the chromophore and residues 145–148 of β‐strand 7.