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Figure 3
Two examples of rare isoleucine rotamers that were unambiguously observed in good electron density in structures determined at around 1.0 Å resolution. Left: Ile337 in chain A of the triacylglycerol lipase protein (PDB entry 1d5t; Brzozowski et al., 2000BB4) is observed in section 1. Right: Ile15 in chain B of the HIV protease (PDB entry 1kzk; Reiling et al., 2002BB47) is observed in section 2. Electron densities were obtained from the EDS server and are contoured at 1.4σ. At http://swift.cmbi.ru.nl/gv/isoleucine/ the local structures of these residues are shown and the interactions that keep the residues in these unfavourable rotamers are explained. MolProbity (Chen et al., 2010BB9) and WHAT_CHECK (Hooft, Vriend et al., 1996BB20) call these two rotamers `poor'. We believe that `improbable' is a better description.

Journal logoSTRUCTURAL
BIOLOGY
ISSN: 2059-7983
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