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Figure 4
Relationships between the Cζ—Oη and Cβ2—Cγ2 bond lengths. Green, cyan and purple circles represent the lengths in GFP variants reported in the Protein Data Bank at higher resolution (<1.3 Å) or referred to in theoretical studies (Supplementary Tables S2 and S3). The proteins are categorized by their reported spectrum or the estimated protonation state of Oη. Those with an absorption peak at a shorter wavelength (∼400 nm) or a protonated Oη are considered to be A-form proteins (green), while those with an absorption peak at a longer wavelength (∼480 nm) or a deprotonated Oη are considered to be B-form proteins (cyan). Those with an ambiguous interpretation are shown in purple. The lengths for the structures in this study (T203I in dark green, S65T in blue and E222Q in yellow) are represented with error bars of the standard deviations as estimated with SHELXL and MoPro. Those of tyrosine are shown in the same manner with the standard deviation for the restraint. Bond lengths optimized by theoretical calculation with or without consideration of the protein environment (`Theo. Protein' or `Isolated') are shown as `×' and `+', respectively. The numbers indicate the references listed in Supplementary Table S3.

IUCrJ
Volume 6| Part 3| May 2019| Pages 387-400
ISSN: 2052-2525
https://doi.org/10.1107/S205225251900246X