Type of research: basic Duration from: 01/01/91. to 12/31/93. Papers on project (total): 40
Papers on project quoted in Current Contents: 17
Institution name: Institut "Ruđer Bošković", Zagreb (98) Department/Institute: Department of Organic Chemistry and Biochemistry Address: Bijenička c. 54 City: 10000 - Zagreb, Croatia
Communication
Phone: 385 (01) 4561-111/1202
Fax: 385 (01) 425-647
E-mail: magnu@olimp.irb.hr
Summary: Derivatives of the plant hormone (auxin),
indole-3-acetic acid (IAA) were prepared. These included ring-halogenated
and -alkylated IAAs and amino acid and sugar conjugates of IAA, some of
which were labeled with stable isotopes. The compounds were used in
structural, biological and biochemical studies. Molecular structures and
conformations in solution were investigated by X-ray crystallography, NMR
NOE-measurements, and computational methods, in close collaboration with
expert colleagues from the Ruđer Bošković Institute and foreign
institutions. The results were correlated with biological activity as
determined in short-term assays and in plant tissue culture. The structural
data were also used in a search for ways of immobilizing IAA as a ligand
linked to macromolecular carriers with minimal interference with its auxin
properties. Biochemical studies included experiments on the function of
indole in IAA biogenesis in normal and transgenic plants carrying modified
tryptophan-synthesis genes.
Research goals: At present, crop plants are manipulated to
human needs using massive amounts of agrochemicals. This would not be
necessary if the endogenous mechanisms controlling growth and development
were known in detail and could be optimally exploited or redirected as
needed. That this is possible has recently been shown in tomato plants
modified in their capability to make the plant hormone, ethylene: their
fruits remain firm and marketable for a much longer time than standard
tomatoes. We wish to contribute to a better understanding of plant
development by elucidating the physiology, biochemistry and chemistry of
another class of plant hormones, the auxins with indole-3-acetic acid
(IAA) as the most common representative. During the past five-year period,
we have focused on structure-activity relationships. Our structural data
were based on X-ray diffraction analysis in crystals, from which the
conformation in solution was deduced by recently developed computational
methods. This is a large step forward, compared to the previous approach
of deriving molecular structure by eye inspection of mechanical (e. g.
ball-and-stick) models. The structural data obtained were used in attempts
to immobilize IAA at macromolecular carriers in a way that does not
impede recognition by auxin-binding proteins. Such carrier-linked IAA
should be an ideal affinity sorbent for isolating auxin receptors from
plant tissues.
COOPERATION - PROJECTS
Name of project
: JF-813 Immunochemical determination of plant
indoleacetic acid Name of institution: Yugoslav-United States Joint Fund for
Scientific and Technological Cooperation City: Washington, D.C., SAD
Name of project
: CI1*-CT 91-0891 Conformation and molecular
dynamics of biologically active (plant) glycosides (and related compounds) Name of institution: Europska unija
Name of project
: JF 202 Molecular Tools for Research on the
Plant Hormone (Auxin) Indole-3-acetic Acid Name of institution: United Stated - Croatian Joint Fund (cordinated
by the United States Department of Agriculture) City: Washington, D.C., SAD
COOPERATION - INSTITUTIONS
Name of institution
: Sveriges Lantbruksuniversitet,
Institutionen for Skoglig Genetik och Vaxtfysiologi Type of institution: University/Faculty Type of cooperation: Occasional exchange of experts City: Umea, Švedska
Name of institution
: Division of Nuclear Medicine and
Biophysics, Department of Pharmacology, UCLA School of Medicine Type of institution: University/Faculty Type of cooperation: Occasional exchange of experts City: 90024 - Los Angeles, SAD
Name of institution
: Department of Horticultural Science,
University of Minnesota Type of institution: University/Faculty Type of cooperation: Occasional exchange of experts City: Saint Paul, SAD
Name of institution
: United States Department of Agriculture,
Agricultural Research Service, Beltsville Agricultural Research Center West Type of institution: State institute Type of cooperation: Joint project City: Beltsville, MD, SAD
Name of institution
: Medical Foundation of Buffalo, Inc Type of institution: Non-profit Type of cooperation: Joint publishing of scientific papers City: Buffalo, N.Y., SAD
Name of institution
: Department of Crystal and Structural
Chemistry, Bijvoet Center for Biomolecular Research, Rijksuniversiteit
Utrecht Type of institution: University/Faculty Type of cooperation: Joint publishing of scientific papers City: Utrecht, Nizozemska Other information about the project.