International Union of Pure and Applied Chemistry Iupac-iubmb-iupab Inter-union Task Group on the Standardization of Data Bases of Protein and Nucleic Acid Structures Determined by Nmr Spectroscopy Recommendations for the Presentation of Nmr Structures of Proteins and Nucleic Acids

The recommendations presented here are designed to support easier communication of NMR data and NMR structures of proteins and nucleic acids through unified nomenclature and reporting standards. Much of this document pertains to the reporting of data in journal articles; however, in the interest of the future development of structural biology, it is desirable that the bulk of the reported information be stored in computer-accessible form and be freely accessible to the scientific community in standardized formats for data exchange. These recommendations stem from an IUPAC-IUBMB-IUPAB inter-union venture with the direct involvement of ICSU and CODATA. The Task Group has reviewed previous formal recommendations and has extended them in the light of more recent developments in the field of biomolecular NMR spectroscopy. Drafts of the recommendations presented here have been examined critically by more than 50 specialists in the field and have gone through two rounds of extensive modification to incorporate suggestions and criticisms. TABLE OF CONTENTS Page Introduction .............................................................................................. 119 1. Definition of the system studied .....................................................................120 1.1. Names of the molecules used ................................................................ 120 1.2. Source ......................................................................................120 1.3. Evidence for homogeneity and chemical identity .................................. 120 1.4. Sequence or chemical structure ............................................................ 120 1.5. Solution conditions ............................................................................. 120 1.6. Isotope-labeled proteins and nucleic acids .......................................... 121 2. Atom identifiers for reporting chemical shift assignments .................................. 121 2.1. Proteins and peptides .....................................................................121 2.1.1. Standard nomenclature ............................................................ 121 2.1.2. Notation for assignment ambiguities .......................................... 123 2.1.2.1. Non-stereochemical ambiguity .................................. 123 2.1.2.2. Stereochemical ambiguity involving prochiral centers .........123 2.1.2.3. Other stereochemical ambiguity .................................. 123 2.2. Nucleic acids ............................................................................. 124 2.2.1. Standard nomenclature ............................................................ 124 2.2.2. Notation for assignment ambiguities .......................................... 124