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Figure 8.
Figure 8. Conformational changes of the KMSKS loop. (a)
Open conformation of the KMSKS loop in the E. coli
TyrRS·L-tyrosine structure. (b) Semi-open conformation of
the KMSKS loop in the E. coil TyrRS·Tyr-AMS structure.
The superposition of the open-form KMSKS loop is also shown by a
pink translucent tube. (c) Closed conformation of the KMSKS loop
in the T. thermophilus
TyrRS·ATP·L-tyrosinol·tRNA^Tyr structure13
(PDB ID: 1H3E). The KMSKS loops are shown by orange tubes. The
carbon atoms of L-tyrosine and L-tyrosinol are shown in pink,
and those of Tyr-AMS are shown in light blue, respectively. (d)
The bottleneck of the catalytic site in the T. thermophilus
TyrRS closed form. The surface model of Tyr-AMP phosphate, which
is a landmark of the aminoacyl transfer center, is shown by a
stick model. (e) The 3'-adenosine of the tRNA cannot pass
through the bottleneck of (d). The adenosine moiety is shown by
a CPK model. (f) The exposed catalytic site in the E. coli TyrRS
semi-open form. Tyr-AMS is shown by a stick model. The molecular
surfaces were produced using the program MSMS
(http://www.scripps.edu/mb/olson/people/sanner/html/msms_home.html).
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