This directory contains files derived from real NMR data for CASP14 target N1077.



The 13C,15N enriched protein sample was produced in the laboratories of Gaetano Montelione at Rensselaer Polytechnic Institute and Masayori Inouye at Rutgers. This integral membrane protein sample was prepared in micelles, using perdeuterated detergents.  The protein is believed to be a monomer under these conditions.



NMR data was collected by S. McCallum, and analyzed by G. Liu.  Data collection included standard triple-resonance NMR experiments for backbone and sidechain amide and methyl resonance assignments, as well as 3D N-NOESY.  



The NMR analysis included only backbone HN, N, Ca, Cb, and C' resonances, sidechain amide H and N resonances, and some sidechain H and C methyl resonances assignments. These classes of resonance assignments can be obtained most rapidly even for larger (15 - 60 kDa) perdeuterated proteins.  Some of the ambiguous contacts are False Positives (i.e. none of the possible contacts listed is true).  This may be true of as much as 10% of the Ambiguous Contacts.



The Ambiguous Contact List was generated from these resonance assignments and real NOESY peak lists using Cycle0 of the program ASDP (formally AutoStructure) [Y.J. Huang, R. Tejero, R. Powers, and G.T. Montelione, G.T. Proteins 62, 587-603 (2006)].  The distance estimates are approximate, and may be best treated simply as contacts with d < 5.0 Ang.

In the NOESY spectrum there are diagonal peaks - with correspond the HN(i) -> HN(i).  These are Òself peaksÓ and are not contact restraints However - there may be a long-range contact which accidentally have almost the same identical position in the spectrum as a diagonal peak; i.e. they overlap. For this reason - there are NOESY peaks assigned to "self peaks" which may also have possible assignments to long-range contacts.

Any residue number with  index <=0 is in the N-terminal purification tag residue, which is excluded from the released protein sequence.



Dihedral Restraints were determined from these backbone resonance assignments using Talos_N [Y. Shen, and A. Bax, J. Biomol. NMR, 56, 227-241(2013)].



There are no RDCs available for this target.



This sparse NMR data collection strategy can provide accurate structures, when combined with advanced modeling methods.



The high-accuracy reference structure, based on additional NMR data, will be provided for assessment.



G. T. Montelione

Y.J. Huang

CASP NMR Assessors
Rensselaer Polytechnic Institute
monteg3@rpi.edu