Globin interactions with lipids and membranes.

Many bacterial globins have been demonstrated to interact with membrane lipids, and several hypotheses in support of a functional role for membrane localization have been set forth. Bacterial globins have been suggested to facilitate oxygen diffusion to terminal oxidases, to protect oxidases from nitric oxide or eventually to preserve the integrity of the membrane lipids through peroxide-reducing activities as a response to oxidative/nitrosative stress. In this framework, methodological approaches to the study of globin-membrane interactions need to be analyzed in depth in order to single out the relevant features of these interactions and to clearly distinguish the specific membrane and lipid binding process from trivial effects related to the possible partitioning of the lipid side chains to the hydrophobic heme pocket or to the presence of partially folded, insoluble protein aggregates within membranous pellets. Methods for qualitative lipid analysis, liposome-protein binding studies, and analysis of protein insertion into lipid monolayer are thus described with the aim of providing rapid and efficient screening of specific globin-membrane interactions.