文摘
Acyl carrier protein (ACP) is a small, highly conserved protein with an essential role in amyriad of reactions throughout lipid metabolism in plants and bacteria where it interacts with a remarkablediversity of proteins. The nature of the proper recognition and precise alignment between the proteinmoieties of ACP and its many interactive proteins is not understood. Residues conserved among ACPsfrom numerous plants and bacteria were considered as possibly being crucial to ACP's function, includingprotein-protein interaction, and a method of identifying amino acid residue clusters of high hydrophobicityon ACP's surface was used to estimate residues possibly involved in specific ACP-protein interactions.On the basis of this information, single-site mutation analysis of multiple residues, one at a time, of ACPwas used to probe the identities of potential contact residues of ACPSH or acyl-ACP involved in specificinteractions with selected enzymes. The roles of particular ACP residues were more precisely defined bysite-directed fluorescence analyses of various myristoyl-mutant-ACPs upon specific interaction with theEscherichia coli hemolysin-activating acyltransferase, HlyC. This was done by selectively labeling eachmutated site, one at a time, with an environmentally sensitive fluoroprobe and observing its fluorescencebehavior in the absence and presence of HlyC. Consequently, a picture of the portion of ACP involvedin selected macromolecular interaction has emerged.