Brief description of what's out there and what we've got.
- EYFP (is what people are usually referring to when they say just YFP)
- GFP with S65G/S72A/T203Y
- Citrine (Griesbeck JBC'01)
- EYFP with V68L/Q69M
- Venus (Nagai NBT'02)
- EYFP with F46L/F64L/M153T/V163A/S175G
- Our "Venus" (aka Citrus)
- Venus with V68L/Q69M
- Silver's Venus (Surprisingly, approx 8 fold less bright than Citrus when expressed in E.coli; expression may be the problem, rather than brightness)
- Citrus with V68L / R80Q / H231L
- Citrus-LAA+2 (NY sequence repeated as spacer between ClpX and SspB binding sites)
- weak RBS - Citrus
- weak RBS - Citrus-LAA
- YPet (Nguyen NBT'05)
Venus with I47L/S208F/V224L/H231E/D234N
What mutations do
F46L: faster maturation at 37deg 
F64L: reduced sensitivity to pH and Cl-, folding
V68L: reduced sensitivity to pH 
Q69M: 2x photostabilty, lower pKa (5.7), indifference to chloride, better expression at 37deg and in organelles 
A206K: monomer (instead of weak dimer)
- Nagai T, Ibata K, Park ES, Kubota M, Mikoshiba K, and Miyawaki A. . pmid:11753368.
- Miyawaki A, Griesbeck O, Heim R, and Tsien RY. . pmid:10051607.
- Griesbeck O, Baird GS, Campbell RE, Zacharias DA, and Tsien RY. . pmid:11387331.