An automated technique for the sequential assignment of NMR backbone resonances of oriented protein samples has been developed and tested based on 15N-15N homonuclear exchange and spin-exchanged separated local-field spectra. By treating the experimental spectral intensity as a pseudopotential, the Monte-Carlo Simulated Annealing algorithm has been employed to seek lowest-energy assignment solutions over a large sampling space where direct enumeration would be unfeasible. The determined sequential assignments have been scored based on the positions of the crosspeaks resulting from the possible orders for the main peaks. This approach is versatile in terms of the parameters that can be specified to achieve the best-fit result. At a minimum the algorithm requires a continuous segment of the main-peak chemical shifts obtained from a uniformly labeled sample and a spin-exchanged experimental spectrum represented as a 2D matrix array. With selective labeling experiments, groups of chemical shifts corresponding to specific locations in the protein backbone can be fixed, thereby decreasing the sampling space. The output from the program consists of a list of top-score main peak assignments, which can be subjected to further scoring criteria until a consensus solution is found. The algorithm has first been tested on a synthetic spectrum with randomly generated chemical shifts and dipolar couplings for the main peaks. The original assignments have been successfully recovered for as many as 100 main peaks when residue-type information was used even in the presence of substantial spectral peak overlap. The algorithm was then applied to assigning two sets of experimental spectra to recover and confirm the previously established assignments in an automated fashion. For the 20-residue transmembrane domain of Pf1 coat protein reconstituted in magnetically aligned bicelles, the original assignment by Park et al. (2010) was recovered by the automated algorithm with additional input from 5 selectively labeled amino acid spectra. The second case considered was the 46 residue Pf1 bacteriophage from Thiriot et al. (2005) and Knox et al. (2010), of which 38 residues were fit. Automated fitting resulted in several possible assignments but not exactly the original assignment. By using a post-fitting filtering procedure based on the number of missed cross peaks and Pf1 helical structure, a consensus spectroscopic assignment is proposed covering 84% of the original assignment. While the automated assignment works best in spectra with well-resolved crosspeaks, it also tolerates substantial spectral crowding to yield reasonable assignments in the cases where ambiguity and degeneracy of possible assignment solutions are inevitable.
[NMR paper] Automated assignment of NMR spectra of macroscopically oriented proteins using simulated annealing.
Automated assignment of NMR spectra of macroscopically oriented proteins using simulated annealing.
Related Articles Automated assignment of NMR spectra of macroscopically oriented proteins using simulated annealing.
J Magn Reson. 2018 Jun 16;293:104-114
Authors: Lapin J, Nevzorov AA
Abstract
An automated technique for the sequential assignment of NMR backbone resonances of oriented protein samples has been developed and tested based on 15N-15N homonuclear exchange and spin-exchanged separated local-field spectra. By treating the...
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[NMR paper] Automated assignment of NMR spectra of macroscopically oriented proteins using simulated annealing
Automated assignment of NMR spectra of macroscopically oriented proteins using simulated annealing
Publication date: August 2018
Source:Journal of Magnetic Resonance, Volume 293</br>
Author(s): Joel Lapin, Alexander A. Nevzorov</br>
An automated technique for the sequential assignment of NMR backbone resonances of oriented protein samples has been developed and tested based on 15N-15N homonuclear exchange and spin-exchanged separated local-field spectra. By treating the experimental spectral intensity as a pseudopotential, the Monte-Carlo Simulated Annealing...
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A general Monte Carlo/simulated annealing algorithm for resonance assignment in NMR of uniformly labeled biopolymers
A general Monte Carlo/simulated annealing algorithm for resonance assignment in NMR of uniformly labeled biopolymers
Abstract We describe a general computational approach to site-specific resonance assignments in multidimensional NMR studies of uniformly 15N,13C-labeled biopolymers, based on a simple Monte Carlo/simulated annealing (MCSA) algorithm contained in the program MCASSIGN2. Input to MCASSIGN2 includes lists of multidimensional signals in the NMR spectra with their possible residue-type assignments (which need not be unique), the biopolymer sequence, and a table that describes...
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[NMR paper] Protein heteronuclear NMR assignments using mean-field simulated annealing.
Protein heteronuclear NMR assignments using mean-field simulated annealing.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Protein heteronuclear NMR assignments using mean-field simulated annealing.
J Magn Reson. 1997 Mar;125(1):34-42
Authors: Buchler NE, Zuiderweg ER, Wang H, Goldstein RA
A computational method for the assignment of the NMR spectra of larger (21 kDa) proteins using a set of six of the most sensitive heteronuclear multidimensional nuclear magnetic...
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[NMR paper] Protein heteronuclear NMR assignments using mean-field simulated annealing.
Protein heteronuclear NMR assignments using mean-field simulated annealing.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles Protein heteronuclear NMR assignments using mean-field simulated annealing.
J Magn Reson. 1997 Mar;125(1):34-42
Authors: Buchler NE, Zuiderweg ER, Wang H, Goldstein RA
A computational method for the assignment of the NMR spectra of larger (21 kDa) proteins using a set of six of the most sensitive heteronuclear multidimensional nuclear magnetic...
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08-22-2010 03:03 PM
[NMR paper] Simulated annealing with restrained molecular dynamics using a flexible restraint pot
Simulated annealing with restrained molecular dynamics using a flexible restraint potential: theory and evaluation with simulated NMR constraints.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www.pubmedcentral.nih.gov-corehtml-pmc-pmcgifs-pubmed-pmc.gif Related Articles Simulated annealing with restrained molecular dynamics using a flexible restraint potential: theory and evaluation with simulated NMR constraints.
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[NMR paper] Application of neural networks to automated assignment of NMR spectra of proteins.
Application of neural networks to automated assignment of NMR spectra of proteins.
Related Articles Application of neural networks to automated assignment of NMR spectra of proteins.
J Biomol NMR. 1994 Jan;4(1):35-46
Authors: Hare BJ, Prestegard JH
Simulated neural networks are described which aid the assignment of protein NMR spectra. A network trained to recognize amino acid type from TOCSY data was trained on 148 assigned spin systems from E. coli acyl carrier proteins (ACPs) and tested on spin systems from spinach ACP, which has a 37%...
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[NMR paper] Application of neural networks to automated assignment of NMR spectra of proteins.
Application of neural networks to automated assignment of NMR spectra of proteins.
Related Articles Application of neural networks to automated assignment of NMR spectra of proteins.
J Biomol NMR. 1994 Jan;4(1):35-46
Authors: Hare BJ, Prestegard JH
Simulated neural networks are described which aid the assignment of protein NMR spectra. A network trained to recognize amino acid type from TOCSY data was trained on 148 assigned spin systems from E. coli acyl carrier proteins (ACPs) and tested on spin systems from spinach ACP, which has a 37%...