{"title":"Membrane protein structure determination from Paramagnetic Relaxation Enhancement and internuclear distance restraints.","authors":"Raoul F Vaz, Leonid S Brown, Vlad Ladizhansky","doi":"10.1007/s10858-025-00467-w","DOIUrl":null,"url":null,"abstract":"<p><p>Magic angle spinning nuclear magnetic resonance (MAS NMR) is well suited for the determination of protein structure. The key structural information is obtained in the form of spectral cross peaks between spatially close nuclear spins, but assigning these cross peaks unambiguously to unique spin pairs is often a tedious task because of spectral overlap. Here, we use a seven-helical membrane protein Anabaena Sensory Rhodopsin (ASR) as a model system to demonstrate that transverse Paramagnetic Relaxation Enhancements (PRE) extracted from 2D MAS NMR spectra could be used to obtain a protein structural model. Starting with near complete assignments (93%) of ASR residues, TALOS + predicted backbone dihedral angles and secondary structure restraints in the form of backbone hydrogen bonds are combined with PRE-based restraints and used to generate a coarse model. This model is subsequently utilized as a template reference to facilitate automated assignments of highly ambiguous internuclear correlations. The template is used in an iterative cross peak assignment process and is progressively improved through the inclusion of disambiguated restraints, thereby converging to a low root-mean-square-deviation structural model. In addition to improving structure calculation conversion, the inclusion of PREs also improves packing between helices within an alpha-helical bundle.</p>","PeriodicalId":613,"journal":{"name":"Journal of Biomolecular NMR","volume":" ","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2025-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Biomolecular NMR","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1007/s10858-025-00467-w","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Magic angle spinning nuclear magnetic resonance (MAS NMR) is well suited for the determination of protein structure. The key structural information is obtained in the form of spectral cross peaks between spatially close nuclear spins, but assigning these cross peaks unambiguously to unique spin pairs is often a tedious task because of spectral overlap. Here, we use a seven-helical membrane protein Anabaena Sensory Rhodopsin (ASR) as a model system to demonstrate that transverse Paramagnetic Relaxation Enhancements (PRE) extracted from 2D MAS NMR spectra could be used to obtain a protein structural model. Starting with near complete assignments (93%) of ASR residues, TALOS + predicted backbone dihedral angles and secondary structure restraints in the form of backbone hydrogen bonds are combined with PRE-based restraints and used to generate a coarse model. This model is subsequently utilized as a template reference to facilitate automated assignments of highly ambiguous internuclear correlations. The template is used in an iterative cross peak assignment process and is progressively improved through the inclusion of disambiguated restraints, thereby converging to a low root-mean-square-deviation structural model. In addition to improving structure calculation conversion, the inclusion of PREs also improves packing between helices within an alpha-helical bundle.
期刊介绍:
The Journal of Biomolecular NMR provides a forum for publishing research on technical developments and innovative applications of nuclear magnetic resonance spectroscopy for the study of structure and dynamic properties of biopolymers in solution, liquid crystals, solids and mixed environments, e.g., attached to membranes. This may include:
Three-dimensional structure determination of biological macromolecules (polypeptides/proteins, DNA, RNA, oligosaccharides) by NMR.
New NMR techniques for studies of biological macromolecules.
Novel approaches to computer-aided automated analysis of multidimensional NMR spectra.
Computational methods for the structural interpretation of NMR data, including structure refinement.
Comparisons of structures determined by NMR with those obtained by other methods, e.g. by diffraction techniques with protein single crystals.
New techniques of sample preparation for NMR experiments (biosynthetic and chemical methods for isotope labeling, preparation of nutrients for biosynthetic isotope labeling, etc.). An NMR characterization of the products must be included.