This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. In previous work on channel formation using spin labeled Gramicidin A (GAsl) we found that the non-channel form prevails in the gel phase of mismatching lipids (DPPC, DSPC). We have now addressed the assignment of non-channel forms and studied the complex equilibrium in the gramicidin/lipid system, which includes channels (i.e. head-to-head dimers [HHD]), non-channel dimers, and monomers. To study non-channel forms of spin labeled GA, which can aggregate, we labeled two different sites on the same gramicidin molecule, instead of measuring the distance between spin labels attached at the same position on both dimer-forming molecules. This intramolecular distance between the spin labels could be used as a fingerprint of the particular conformation. Interactions between spin labels on different gramicidin molecules were eliminated by substantially diluting the double spin-labeled gramicidin by unlabeled gramicidin. Several new spin labeled gramicidin compounds were synthesized and used. In octanol, gramicidin exists mainly as a double helical (DH) left-handed antiparallel dimer, and we determined interspin distances for this structure. GAD with both N- and C-termini labeled and GALN, single-labeled at the N-terminus, substantially impair their propensity to HHD formation. In most lipids we observed two different conformations of GAD. The interspin distance in the main fraction (20.0?) is consistent with the monomeric state. Double helices (31.6?, exactly as in octanol) are a minor component with the fraction changing in the saturated lipid series in the following order: DLPC

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR016292-10
Application #
8172109
Study Section
Special Emphasis Panel (ZRG1-BCMB-K (40))
Project Start
2010-09-01
Project End
2011-08-31
Budget Start
2010-09-01
Budget End
2011-08-31
Support Year
10
Fiscal Year
2010
Total Cost
$3,915
Indirect Cost
Name
Cornell University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
872612445
City
Ithaca
State
NY
Country
United States
Zip Code
14850
Jain, Rinku; Vanamee, Eva S; Dzikovski, Boris G et al. (2014) An iron-sulfur cluster in the polymerase domain of yeast DNA polymerase ?. J Mol Biol 426:301-8
Pratt, Ashley J; Shin, David S; Merz, Gregory E et al. (2014) Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes. Proc Natl Acad Sci U S A 111:E4568-76
Georgieva, Elka R; Borbat, Peter P; Ginter, Christopher et al. (2013) Conformational ensemble of the sodium-coupled aspartate transporter. Nat Struct Mol Biol 20:215-21
Airola, Michael V; Sukomon, Nattakan; Samanta, Dipanjan et al. (2013) HAMP domain conformers that propagate opposite signals in bacterial chemoreceptors. PLoS Biol 11:e1001479
Airola, Michael V; Huh, Doowon; Sukomon, Nattakan et al. (2013) Architecture of the soluble receptor Aer2 indicates an in-line mechanism for PAS and HAMP domain signaling. J Mol Biol 425:886-901
Sun, Yan; Zhang, Ziwei; Grigoryants, Vladimir M et al. (2012) The internal dynamics of mini c TAR DNA probed by electron paramagnetic resonance of nitroxide spin-labels at the lower stem, the loop, and the bulge. Biochemistry 51:8530-41
Smith, Andrew K; Freed, Jack H (2012) Dynamics and ordering of lipid spin-labels along the coexistence curve of two membrane phases: an ESR study. Chem Phys Lipids 165:348-61
Yu, Renyuan Pony; Darmon, Jonathan M; Hoyt, Jordan M et al. (2012) High-Activity Iron Catalysts for the Hydrogenation of Hindered, Unfunctionalized Alkenes. ACS Catal 2:1760-1764
Gaffney, Betty J; Bradshaw, Miles D; Frausto, Stephen D et al. (2012) Locating a lipid at the portal to the lipoxygenase active site. Biophys J 103:2134-44
Dzikovski, Boris; Tipikin, Dmitriy; Freed, Jack (2012) Conformational distributions and hydrogen bonding in gel and frozen lipid bilayers: a high frequency spin-label ESR study. J Phys Chem B 116:6694-706

Showing the most recent 10 out of 72 publications