Betty J. Gaffney

Area of research

Biophysics · Molecular Biology

Research interest

Research topics from publications: Structure and interaction with phospholipids of a prokaryotic lipoxygenase from Pseudomonas aeruginosa; Locating a Lipid at the Portal to the Lipoxygenase Active Site; Connecting Lipoxygenase Function to Structure by Electron Paramagnetic Resonance; Fluctuations of an Exposed π-Helix Involved in Lipoxygenase Substrate Recognition; EPR Spectroscopic Studies of Lipoxygenases; Entrance to a lipoxygenase substrate cavity is defined; Functional Conformational Changes in Lipoxygenase. Representative work: Lipoxygenases (LOXs), which are essential in eukaryotes, have no confirmed function in prokaryotes that are devoid of polyunsaturated fatty acids. The structure of a secretable LOX from Pseudomonas aeruginosa ( Pa _LOX), the first available from a prokaryote, presents significant differences with respect to eukaryotic LOXs, including a cluster of helices acting as a lid to the active center. The mobility of the lid and the structural variability of the N‐terminal region of Pa _LOX was confirmed by comparing 2 crystal forms. The binding pocket contains a phosphatidylethanolamine phospholipid with branches of 18 ( sn ‐1) and 14/16 ( sn ‐2) carbon atoms in length. Carbon atoms from the sn‐1 cha CONSPECTUS: Lipoxygenase enzymes insert oxygen in a polyunsaturated lipid, yielding a hydroperoxide product. When the acyl chain is arachidonate, with three cis-pentadiene units, 12 positionally and stereochemically different products might result. The plant lipids, linoleate and linolenate, have, respectively, four and eight potential oxygen insertion sites. The puzzle of how specificity is achieved in these reactions grows as more and more protein structures confirm the conservation of a lipoxygenase protein fold in plants, animals, and bacteria. Lipoxygenases are large enough (60-100 kDa) that they provide a protein shell completely surrounding an active site cavity that has the shape of