ISBN: 978-83-60043-10-3 - eurobic9

Eurobic9, 2-6 September, 2008, Wrocław, Poland
P111. Correlating Properties, Structure and Function in the EcI/II
Metallothionein from Wheat Embryos
O. Leszczyszyn a , E. Peroza b , E. Freisinger b , C. Blindauer a
a Department of Chemistry, University of Warwick, Gibbett Hill Road, CV4 7AL, Coventry, United Kingdom,
b Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse 190, CH-8057, Zürich,
Switzerland
e-mail: o.i.leszczyszyn@warwick.ac.uk
Over the last decade, the advancement of genome sequencing, microarray and high-throughput protein
identification techniques has resulted in an exponential increase in the number of plant metallothionein (pMT)
sequences in protein and translated nucleotide databases. More and more evidence shows that the four pMT
subfamilies are differentially expressed during various developmental stages and in different organs [1], and
that they display significant variation in the number and arrangement of CXC motifs [2]. Therefore, it is
reasonable to suggest that pMTs carry out compartmentalised roles for which they possess specific properties.
However, the relative paucity of structural and biochemical information for pMTs severely limits the scope for
the correlation of properties with structure and function. Therefore, further research focussing on both structure
and metal binding dynamics is required to advance our understanding in this field.
Given the critical need for structural and biochemical information on pMTs, our research focuses on the
elucidation of the solution structure of wheat EcI/II; the prototype type 4 pMT. In addition, we have probed
both the kinetics and thermodynamics of metal binding using a range of techniques, including multinuclear
NMR, mass spectrometry and molecular biology. These studies show that EcI/II binds six zinc ions in two
distinct domains with stoichiometries of Zn2Cys6 and Zn4Cys11His2 [3-4]. Structure calculations reveal that the
individual EcI/II domains possess unique structural features not previously reported in MT literature. These
novel structural features confer distinct backbone and metal dynamic properties to each domain, and are likely
to have a functional significance.
References:
[1] N.J. Robinson, A.M. Tommey, C. Kuske, P.J. Jackson, Biochem J, 295, 1-10 (1993)
[2] C. Cobbett, P. Goldsbrough, Annu Rev Plant Biol, 53, 159-168 (2002)
[3] O.I. Leszczyszyn, R. Schmidt, C.A. Blindauer, Proteins: Struc Func Bioinf, 68, 922-935 (2007)
[4] E.A. Peroza, E. Freisinger, J Biol Chem, 12(3), 377-391 (2007)
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