The interface of a membrane-spanning leucine zipper mapped by asparagine-scanning mutagenesis.
An oligo-leucine sequence has previously been shown to function as an artificial transmembrane segment that efficiently self-assembles in membranes and in detergent solution. Here, a novel technique, asparagine-scanning mutagenesis, was applied to probe the interface of the self-assembled oligo-leucine domain. This novel approach identifies interfacial residues whose exchange to asparagine leads to enhanced self-interaction of transmembrane helices by interhelical hydrogen bond formation. As analyzed by the ToxR system in membranes, the interface formed by the oligo-leucine domain is based on a leucine-zipper-like heptad repeat pattern of amino acids. In general, the strongest impacts on self-assembly were seen with asparagines located around the center of the sequence, indicating that interaction is be more efficient here than at the termini of the transmembrane domains.
Ruan
Weiming
W
Lehrstuhl für Chemie der Biopolymere, Technische Universität München, Weihenstephaner Berg 3, D-85354 Freising-Weihenstephan, Germany.
Lindner
Eric
E
Langosch
Dieter
D
D000595:Amino Acid Sequence; D001216:Asparagine / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites; D007930:Leucine / Q000235:genetics / Q000378:metabolism; D016350:Leucine Zippers / Q000502:physiology*; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000235:genetics*
D008565:Membrane Proteins; D001216:Asparagine; D007930:Leucine