title: Fast NMR data acquisition from bicelles containing a membrane-associated peptide at natural-abundance.
abstract: In spite of recent technological advances in NMR spectroscopy, its low sensitivity continues to be a major limitation particularly for the structural studies of membrane proteins. The need for a large quantity of a membrane protein and acquisition of NMR data for a long duration are not desirable. Therefore, there is considerable interest in the development of methods to speed up the NMR data acquisition from model membrane samples. In this study, we demonstrate the feasibility of acquiring two-dimensional spectra of an antimicrobial peptide (MSI-78; also known as pexiganan) embedded in isotropic bicelles using natural-abundance (15)N nuclei. A copper-chelated lipid embedded in bicelles is used to speed-up the spin-lattice relaxation of protons without affecting the spectral resolution and thus enabling fast data acquisition. Our results suggest that even a 2D SOFAST-HMQC spectrum can be obtained four times faster using a very small amount (∼3 mM) of a copper-chelated lipid. These results demonstrate that this approach will be useful in the structural studies of membrane-associated peptides and proteins without the need for isotopic enrichment for solution NMR studies.
authors.affiliation: Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, United States.
authors.forename: Kazutoshi
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Subramanian
authors.initials: S
authors.lastname: Vivekanandan
authors.forename: Ayyalusamy
authors.initials: A
authors.lastname: Ramamoorthy
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism*; D003300:Copper / Q000737:chemistry; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D009587:Nitrogen Isotopes / Q000737:chemistry; D010742:Phospholipid Ethers / Q000737:chemistry; D011522:Protons
chemical_list: C052298:1,2-dihexadecyl-sn-glycero-3-phosphocholine; D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D009587:Nitrogen Isotopes; D010742:Phospholipid Ethers; D011522:Protons; D003300:Copper; C093828:pexiganan; D004134:Dimyristoylphosphatidylcholine