<!DOCTYPE IUCR-ART
PUBLIC "IUCr//DTD IUCr article dtd V1.1//EN"><iucr-art
jid="D000000" aid="xx0000" access="pay"
docsubty="XL" crt="International Union of Crystallography"
language="0"><jnlinfo name="Acta Crystallographica Section
D" yr="2002" issue="1" volume="58"
abbrtitle="Acta Cryst. D" coden="ABCRE6" editor="Jenny
P. Glusker" issn="0907-4449" fpage="0"
lpage="0"><fm><atl>Crystallization of the novel
flavodoxine-like protein, WrbA, - on the way to three-dimensional structure
<aff><oid id="a">Institute of Physical Biology, University
of South Bohemia at Ceske Budejovice, Zamek 136, CZ-373 33 Nove Hrady, <cny>Czech Republic</cny></aff>, a'">Institute of Physical Biology, University
of South Bohemia at Ceske Budejovice and Institute of Landscape Ecology,
Academy of Science of the Czech Republic, Zamek 136, CZ-373 33 Nove Hrady, <cny>Czech Republic</cny></aff>, <aff><oid
id="b">Institute of Chemistry, Johannes Kepler
University, Altenbergerstrasse 69, A-4040 Linz, <cny>Austria</cny></aff>, and <aff><oid id="c">Chemistry Department, Priceton
University, Washington Rd and William St, Princeton, NJ 08544-1009, <cny>USA</cny></aff></aug>.
Keywords: flavodoxine-like
protein; tryptophan-repressor binding protein; WrbA apoprotein; WrbA
holoprotein; FMN; standard crystallization techniques; advanced crystallization
techniques</atl>
Tryptophan (W)-repressor
binding protein A, WrbA, identified as an E. coli stationary-phase protein was named for its reported effect
on the interaction between tryptophan repressor and DNA [1]. Later work [2]
showed that this effect was non-specific, leaving the physiological role of
WrbA unknown. According to sequence analysis and homology modeling [3] WrbA was
identified as the founding member of a new family of flavodoxin-like proteins, which displays low but structurally
significant sequence similarity with the flavodoxins. The members of WrbA
family are predicted to share the open, twisted a/b flavodoxin fold, but with a short conserved
insertion unique for the new family. This structure motif could account for
experimental observations that some family members are dimeric in solution,
including also finding that WrbA creates a dimer-tetramer equilibrium at
micromolar concentrations [2]. Unlike typical flavodoxins [4], these proteins
bind FMN relatively weakly but still specifically. The computer analysis [3]
indicated some structural differences in the flavin-binding pocket, which may
explain the lower affinity of WrbA for FMN. Due to these peculiarities the
structural analysis may aid in understanding the physiological roles of WrbA
family members. These factors motivated
our research for diffraction-quality crystals.
Purified WrbA apoprotein and holoprotein were used for crystallization trials. Standard and advanced crystallization techniques were applied to crystallize mentioned proteins. WrbA apoprotein crystals grown in capillaries were measured directly at synchrotron DESY (beamline X13) in Hamburg (Germany). Crystals diffracted to a resolution of 2.2Å. Attempts with variable growing conditions are performed to improve quality of apo- and holoprotein crystals.
Acknowledgements:
This work is
supported by grants of the
Ministry of Education of the Czech Republic (projects KONTAKT ME640 and LN00A141) to I.K.S. and by NSF grant INT-03-09049 to J.C.
References:
1. Yang, W., Ni, L.
& Somerville, R.L., Proc. Natl. Acad.
Sci., USA 90(1993),
5796-5800.
2. Grandori, R., Khalifah P.,
Boice J.A., Fairman, R., Giovanielli, K. & Carey, J.,
J. Biol. Chem., 273 (1998), 20960-20966.
3. Grandori, R. & Carey, J., Trends Biochem. Sci., 19(1994), 72.
4.
Burnett, R.M., et al., J. Biol. Chem.,.
249(1974), 4383-4392.