MgRNA: Classification of Mg2+ binding sites in RNA crystal structures Back to Classification Home Download this subset in: CSV, XML, JSON List of Mg2+ binding sites in structure 4tpb 4TPB (2.8Å) -- RIBOSOME : Crystal structure of the e. coli ribosome bound to dalfopristin and quinupristin. this file contains the 50s subunit of the second 70s ribosome with dalfopristin and quinupristin bound. List of all 171 Mg2+ binding sites in the PDB structure 4tpb in the full dataset (switch to benchmark dataset) Sites in the table can be ordered by the following fields by clicking the column header: "benchmark dataset", "Coordination Number", "Qv #", "Qs #", "Qe #", "Site type" or "Mg2+ ID" Page 6 of 9 | « Previous | Next » | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

Mg2+ ion Site type Validation parameters PDB ID Mg2+ ID Coordination Number Qv # Qs # Qe # benchmark dataset 4tpb A3020 2Nb 6   0.75   0.75   0.99 yes 4tpb A3093 Pout·3Bout 6   0.75   1.00   0.94 yes 4tpb A3084 Pout·2Bout 6   0.75   0.99   0.72 yes 4tpb A3030 3Pout 6   0.75   0.99   0.88 yes 4tpb A3082 2Pout·Rout·2Bout 6   0.75   0.99   0.91 yes 4tpb A3136 2Pout 6   0.75   0.99   0.81 yes 4tpb A3012 3Pout 6   0.75   1.00   0.83 yes 4tpb A3021 4Bout 6   0.75   1.00   0.90 yes 4tpb A3018 3Pout·Rout·2Bout 6   0.75   1.00   0.88 yes 4tpb A3038 2Pout·3Bout 6   0.75   0.99   0.92 yes 4tpb A3051 4Pout·Bout 6   0.75   1.00   0.57 yes 4tpb A3129 3Pout·2Bout 6   0.75   1.00   0.95 yes 4tpb A3096 2Pout·2Rout·3Bout 6   0.75   1.00   0.93 yes 4tpb A3088 cis-2Oph 6   0.75   0.76   0.89 yes 4tpb A3046 cis-2Oph 6   0.75   0.75   0.78 yes 4tpb A3079 Oph·Nb 6   0.75   0.97   0.98 yes 4tpb A3068 cis-2Oph 6   0.75   0.76   0.89 yes 4tpb A3083 Oph·Ob 6   0.76   0.76   0.94 yes 4tpb A3052 cis-2Oph 6   0.76   0.78   0.82 yes 4tpb A3023 cis-2Oph 6   0.78   0.93   0.92 yes

^# Validation parameters Q_v, Q_s, Q_e are defined in the range of 0 to 1, with 0 indicating poorest reliability and higher value indicating a more reliable site
Q_v measures the agreement of the inner-sphere bond valence summation with the oxidation state of Mg²⁺ (+2)
Q_s measures the geometrical symmetry of the ligands distribution around the Mg²⁺ required for octahedral geometry
Q_e measures the agreement of the isotropic atomic displacement (B) factor and occupancy of the Mg²⁺ compared to those of all atoms in its environment

Site type used in the classification is a string abbreviation of ligand composition in Mg2+ coordination sphere
Abbreviations used for Mg2+ "Site type"	Mg2+ inner-sphere ligands	Geometry for inner-sphere OP	Mg2+ outer-sphere moieties
	Oph phosphate oxygen (OP1/OP2) Or ribose oxygen (O2'/O4')      or oxygen bridging phosphate and ribose (O3'/O5') Ob nucleobase oxygen      Nb nucleobase nitrogen	cis- two OP ligands adopt cis- isoform trans- two OP ligands adopt trans- isoform fac- three OP ligands adopt fac- isoform mer- three OP ligands adopt mer- isoform	Pout phosphate moiety Rout ribose moiety Bout nucleobase moiety
Reference:	Zheng H, Shabalin IG, Handing KB, Bujnicki JM, Minor W. (2015) Magnesium binding architectures in RNA crystal structures: validation, binding preferences, classification, and motif detection. Nucleic Acid Research 43(7):3789-801 [Pubmed].

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