All cellular reactions are catalysed by proteins (enzymes) or RNAs
(ribozymes). Life cannot be understood without understanding how these
molecular biocatalysts function and how they are stabilised. The ongoing
sequencing of entire genomes and the possibilities of manipulating individual
genes at will has led to important progress towards this goal, but central
questions have remained open. Within the Schwerpunktprogramm
(Priority Program) 1170 “Directed Evolution
to Optimize and Understand Molecular Biocatalysts”, the
novel and powerful approach of directed evolution will be used to tailor molecular
biocatalysts and to gain new and crucial insights into their
Directed evolution in vitro imitates millions of years of natural evolution
on the short time scale of laboratory experiments and allows to manipulate
and analyse biocatalysts in a completely new fashion. In a directed evolution
experiment, first large gene libraries are generated by random mutagenesis.
From these libraries novel enzymes or ribozymes are isolated by elaborate
screening or selection techniques, followed by their in-depth biochemical
characterisation (see the scheme). In contrast to
the more traditional rational design, directed evolution does not require a
detailed a priori knowledge of the structure or mechanism of a biocatalyst.
It is, moreover, particularly instructive because it can provide unexpected
solutions that go beyond the original hypothesis.
In the Priority
Program 1170 directed evolution will be used for a dual purpose: first,
to modify and optimise molecular biocatalysts and, second, to approach the
long-standing questions regarding the molecular basis of enzyme and ribozyme
stability, function and evolution from a different perspective. To achieve
these goals, the newly generated enzymes and ribozymes will be analysed by
state-of-the-art tools of protein and nucleic acid chemistry, enzymology,
structural biology, and theoretical chemistry. Specifically, we aim at
answering the following questions:
- What are the possibilities
and where are the limits for optimising enzymes and ribozymes and for
reshaping them to catalyse non-natural reactions?
- Are there common principles
among enzyme- and ribozyme-mediated catalysis?
- How much conformational
stability and flexibility is required for optimal catalysis?
- What is the structural basis
of substrate- and stereo-selectivity of molecular biocatalysts?
Answering these questions will (i) allow to produce tailored biocatalysts
that will be extremely useful for both basic research and industrial
applications and (ii) provide novel insights into the
sequence-structure-function relationship that cannot be obtained by classical
biochemical and biophysical approaches.
Presentations of the Regensburg Meeting, 6.3. -
8.3. 2005 (password protected)
Presentations of the Bremen Workshop,
31.7.- 2.8. 2006 (password protected)
Program of the Bad Herrenalb Meeting, 29.9. - 3.10.2007
Program of the
Regensburg Meeting, 17.9. - 20.9.2009