Chemistry Reference
In-Depth Information
FIGURE 10.11
Comparison of the structures of MR, MLE, and enolase showing the two homologous domains which illustrate divergent
evolution.
(From
Gerlt et al., 2005
. Reproduced with permission from Elsevier.)
Stereoview of the coordination of the two Mg
2
þ
ions in the enolase-(Mg
2
þ
)
2
-2
e
PGA complex.
FIGURE 10.12
(From
Larsen, Wedeking,
Rayment, & Reed, 1996
.
Copyright (1996) American Chemical Society.)
consider here how this very large number of enzymes achieve their structure or sequence specificity, although the
sensitivity of ligand geometry and electrostatic environment of Mg
2
þ
ions is proposed to greatly enhance
substrate recognition and catalytic specificity (for a review, see
Yang, Lee, & Nowotny, 2006
)
, but rather consider
the role of the metal ions. However, it is salutary to recall a few examples of their specificity. Restriction endo-
nucleases each typically recognise a specific six-base-pair sequence, and the more than 3000 type II restriction
endonucleases recognise over 200 different sequences
how is this sequence specificity achieved? Endonucleases
e
