O.A. Sytina, D. J. Heyes, C.N. Hunter, M. T. Alexandre, I. H.M. van Stokkum, R. van Grondelle and M. L. Groot
Conformational changes in an ultrafast light-driven enzyme determine
catalytic activity Nature 456, 1001-1008, 2008
T. M. Kennis and M. L. Groot, Curr Opin Struct Biol 2007 17, 623
’Ultrafast spectroscopy of biological photoreceptors’
L. Groot, L.J.G.W. van Wilderen, M. Di Donato, Photochem.
2007, 6, 501 – 507
’Femtosecond time-resolved and dispersed infrared spectroscopy on
van Wilderen, M.A. van der Horst, I.H.M. Van Stokkum, K.J. Hellingwerf, R.
van Grondelle, M.L. Groot, Proc. Natl. Acad. Sci.
103, 41, 15050-15055
‘Ultrafast infrared spectroscopy reveals key step for
successful entry into photocycle for Photoactive Yellow Protein’
L. Groot, N. P. Pawlowicz, L. van Wilderen, J. Breton, I. H. M. van
Stokkum and R. van Grondelle, Proc. Natl.
Acad. Sci. USA,
2005 102, 37, 13087-13092
'Initial electron donor and acceptor in isolated Photosystem II reaction
centers identified with femtosecond mid-IR spectroscopy'
D. J. Heyes,
C. N. Hunter, I.H.M. van Stokkum, R. van Grondelle and M.L. Groot, 2003
Nature Structural Biology 10,491-492
‘Ultrafast enzymatic reaction dynamics in protochlorophyllide
am interested in elementary reactions in proteins and enzymes. Using
several spectroscopic techniques, mainly visible
pump-midinfrared probe spectroscopy and vis/vis spectroscpy we study
several protein complexes such as:
structure-dynamics-function relationship in photosynthetic complexes,
in collaboration with dr J. Breton (Saclay, FR) and Prof. B. Diner (DuPont,
Photoactive Yellow Protein (in collaboration with prof. K Hellingwerf,
UVA) is a bacterial blue-light sensor. Light absorption by PYP’s
intrinsic chromophore, p-coumaric acid, leads to the initiation of a
photocycle that comprises several distinct intermediates. We have been
able to show that the low quantum yield of isomerization in PYP (0.3)
is most likely determined by the hydrogen bond strength of the
chromophore with one of the protein residues.
color of the fluorescent light emitted by Green Fluorescent Protein (GFP)
depends on a light-induced proton transfer reaction occurring in a
‘proton-wire’ that is formed by the chromophore, a water molecule
(W22), Ser205 and Glu222. We have been able to show that the chain of
proton transfer reactions starts at the acceptor end of the wire.
have started spectroscopic research on proteorhodopsin with the aim to
resolve what controls their multi-functionality, see publication 2.
and hydride transfer in the chlorophyll biosynthetic enzyme
NADPH:protochlorophyllide oxidoreductase. We have reported the first
ultrafast visible pump-probe data on this important enzyme.
We have found that the catalytic mechanism, involving formation
of a transition state and proton and hydride transfer, proceeds with
time constants of 3ps and 400ps. This project is a collaboration with
prof. Hunter (
and dr D. Heyes (
At LCVU we have developed
an experimental setup for the study of protein dynamics via visible pump/midinfrared
probe spectroscopy. This setup has sufficient sensitivity to follow
reaction induced structural changes with atomic resolution, on a time
scale from 100 femtoseconds (10-13s) up to 10 nanoseconds
(10.10-9s). Our setup is unique because, in combination with a
home-developed Lissajous sample scanner, we are able to acquire datasets
under single pulse conditions, and we can monitor the absorption changes
in the visible part of the spectrum at the same time. We are therefore
uniquely positioned to study protein and chromophore dynamics via their
changes in the vibrational absorption, both for cyclic and for non-cyclic
(photoconversion) reactions. The vibrational spectrum of a protein or a
protein-bound chromophore contains a wealth of information about its
structure, the interaction with the environment and the electronic
properties of the molecule. Therefore time-resolved IR spectroscopy is a
powerful tool that can reveal many dynamic structural details of
chromophores. In addition, it can reveal the response of those parts of
the protein that are affected by the reactions that are taking place.
we have started a new research line in the field of Biomedical Photonics.
Using nonlinear or coherent microscopic techniques, we want to develop new
tools for studies on the level of cells and tissue in the field of
biomedical research. To this end we collaborate with neurobiologists prof.
H. Mansvelder, and dr R. Toonen of the CNCR (VU-FALW), dr E Peterman of
VU-FEW/LCVU and prof. G. van Dongen and R. Brakenhoff of the VUMC