The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission.
Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 A crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants.
Ebisawa
Tatsuki
T
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan.
Yamamura
Akihiro
A
Kameda
Yasuhiro
Y
Hayakawa
Kou
K
Nagata
Koji
K
Tanokura
Masaru
M
D000818:Animals; D037421:Anthozoa / Q000737:chemistry*; D003116:Color; D018360:Crystallography, X-Ray; D049452:Green Fluorescent Proteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D009154:Mutation; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
D049452:Green Fluorescent Proteins
J Mol Biol. 2007 Sep 28;372(4):918-926
17692334
Acta Crystallogr D Biol Crystallogr. 2000 Dec;56(Pt 12):1622-4
11092928
Bioinformatics. 2000 Jun;16(6):566-7
10980157
J Biol Chem. 2003 Sep 5;278(36):34167-71
12819206
Acta Crystallogr D Biol Crystallogr. 1993 Jan 1;49(Pt 1):129-47
15299554
Biochemistry. 2009 Jun 9;48(22):4905-15
19371086
Nat Rev Mol Cell Biol. 2002 Dec;3(12):906-18
12461557
EMBO Rep. 2005 Mar;6(3):233-8
15731765
Proc Natl Acad Sci U S A. 2001 Aug 28;98(18):10037-41
11517324
Annu Rev Biochem. 1998;67:509-44
9759496
Biochem J. 2007 Feb 15;402(1):35-42
17117927
Acta Crystallogr Sect F Struct Biol Cryst Commun. 2009 Dec 1;65(Pt 12):1292-5
20054132
J Mol Biol. 1990 Oct 5;215(3):403-10
2231712
Appl Microbiol Biotechnol. 2007 Nov;77(1):1-12
17704916
Science. 1996 Sep 6;273(5280):1392-5
8703075
Methods Biochem Anal. 2006;47:1-13
16335707
Acta Crystallogr D Biol Crystallogr. 1997 May 1;53(Pt 3):240-55
15299926
Nucleic Acids Res. 2007 Jul;35(Web Server issue):W375-83
17452350
Nat Biotechnol. 1996 Oct;14(10):1246-51
9631087
Proc Natl Acad Sci U S A. 2007 Aug 7;104(32):13005-9
17646653
Acta Crystallogr D Biol Crystallogr. 2004 Dec;60(Pt 12 Pt 1):2126-32
15572765