Robert E. Minto
Research
The core of our research efforts is the isolation and
characterization of novel desaturase and acetylenase genes from
plants and club fungi (Basidiomycetes). Structure/function studies
of this class of enzymes and the development of chemical probes will
provide insight into a critical area of biochemistry, unsaturated
fatty acid metabolism, as well as uncover pathways to an expansive
array of bioactive acetylenic natural products. Many of these
compounds have therapeutic and economic potential as antimicrobial
and antiproliferative agents and HIV reverse-transcriptase inhibitors.
Controlled manipulation of unsaturated and acetylenic fatty acid
metabolism in valuable oilseed and vegetable crops may be lead to
altered oil compositions (e.g., enhanced nutritional benefit),
unusual fatty acid components (e.g., eco-friendly lubricants), or
increased fungal resistance. Despite the valuable bioactivities of
these compounds, many details of the unusual enzymatic reactions
required for the formation of acetylenic natural products remain
elusive. A central objective of our research program is the
isolation and
investigation of novel desaturase and acetylenase genes
from plants and gilled fungi
(Basidiomycetes), and the development of
synthetic chemistry to aid in characterization of the corresponding
enzymes.
A specific, current goal is to isolate genes for the acetylenase
enzymes in the Basidiomycetes. High similarity between the known
acetylenases and the desaturases, enzymes responsible for eukaryotic
unsaturated fatty acid biosynthesis, should allow a
structure/function analysis of their mechanistic differences. Of
particular interest is the isolation of acetylenase genes from
Fistulina hepatica and the chanterelle, both edible mushrooms found
in Indiana. Acetylenase and desaturase genes cloned from
chanterelles are active when expressed in yeast. Acetylenic
metabolites from F. hepatica cultures are being isolated by
high-performance liquid chromatography and characterized prior to
genetic studies. In conjunction with these projects, syntheses of
highly unsaturated enzyme substrates and inhibitors are being
developed for use in mechanistic studies of alkyne formation.
A related area of interest examines the roles of unsaturated lipids
in membrane structure and the interactions between plant
acetylenase/desaturase enzymes and lipid bilayers. These structures,
studied in collaboration with
Prof. Gary Lorigan (Miami University, Oxford, OH), are probed by
circular dichroism, solution NMR, and solid-state NMR spectroscopic
methods. An examination of the order and motion in isotopically
labeled lipids in the presence of transmembrane peptides or membrane
components provides insight into the organization of the bilayer.
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Recent Publications
R. E. Minto and B. J. Blacklock "Biosynthesis and function of polyacetylenes and allied
natural products" Prog. Lipid Res. 2008, 47, in press.
V. Ramamoorthy, E. B. Cahoon, J. Li, M. Thokala, R. E. Minto and D. M. Shah
"Glucosylceramide synthase is essential for alfalfa defensin- mediated growth inhibition
but not for pathogenicity of Fusarium graminearum" Mol. Microbiol. 2007, 66, 771-786.
K. Cai, A. E. Hagerman, R. E. Minto and A. Bennick “Decreased polyphenol transport across cultured intestinal cells by a salivary
proline-rich protein” Biochem. Pharmacol. 2006, 71, 1570-1580.
E. S. Karp, W. J. Gibbons Jr., N. Cellar, R. E. Minto and G. A. Lorigan “Solid-state NMR Studies of a Diverged Microsomal Amino-Proximate Δ12-Desaturase Peptide Reveal Causes of Stability in Bilayer: Tyrosine Anchoring and Arginine Snorkeling” Biophys. J. 2006, 90, 1249-1259.
R. E. Minto, P. R. Adhikari, and G. A. Lorigan “A 2H Solid-state NMR Spectroscopic Investigation of Biomimetic Bicelles Containing Cholesterol and Polyunsaturated Phosphatidylcholine”Chem. Phys. Lipids 2004, 132, 55-64.
G. A. Lorigan, P. C. Dave, E. K. Tiburu, K. Damodaran, S. Abu-Baker, E. S. Karp, W. J. Gibbons and R. E. Minto “Solid-State NMR Spectroscopic Studies of an Integral Membrane Protein Inserted Into Aligned Phospholipid Bilayer Nanotube Arrays” J. Am. Chem. Soc. 2004, 126, 9504-9505.
M. T. Hancock, R. E. Minto and A. R. Pinhas “The Conversion of an Aziridine Plus a Phenyl-substituted Amine Oxide or Aminoether to a Benzodiazepine Derivative” Tetrahedron Lett. 2003, 44, 8357-8360.
E. K. Tiburu, P. C. Dave, J. F. Vanlerberghe, T. B. Cardon, R. E. Minto and G. A. Lorigan “An Improved Synthetic And Purification Procedure For The Hydrophobic Segment Of The Transmembrane Peptide Phospholamban” Anal. Biochem. 2003, 318, 146-151.
E. B. Cahoon, J. Schnurr, E. A. Huffman and R. E. Minto "Fungal Responsive Fatty Acid Acetylenases Occur Widely in Evolutionarily Distant Plant Families” Plant J. 2003, 34, 671-83.
Y. Chen, A. E. Hagerman and R. E. Minto “Preparation of 1,2,3,4,6-Penta-O-Galloyl-[U-14C]Glucopyranose” J. Lab. Comp. Radiopharm. 2003, 46, 99-105.
R. E. Minto, W. J. Gibbons Jr., T. B. Cardon and G. A. Lorigan “Synthesis and conformational studies of a transmembrane domain from a diverged microsomal Δ12-desaturase” Analytical Biochem. 2002, 308, 134-140.
L. Zhu and R. E. Minto “Improved Syntheses of Methyl (14E)- and (14Z)-Dehydrocrepenynate: Key Intermediates In Plant and Fungal Polyacetylene Biosynthesis” Tetrahedron Lett. 2001, 42, 3803-3805.
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