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 1q81 1Q81 (2.95Å) -- RIBOSOME : Crystal structure of minihelix with 3' puromycin bound to a- site of the 50s ribosomal subunit. List of all 117 Mg2+ binding sites in the PDB structure 1q81 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 1 of 6 | « Previous | Next » | 1 | 2 | 3 | 4 | 5 | 6

Mg2+ ion Site type Validation parameters PDB ID Mg2+ ID Coordination Number Qv # Qs # Qe # benchmark dataset 1q81 A8060 Or 5   0.34   0.43   0.91 no 1q81 A8099 Or 4   0.22   0.60   0.78 no 1q81 A8053 Ob 6   0.57   0.83   0.32 no 1q81 A8112 Nb 6   0.67   0.81   0.67 yes 1q81 A8111 Nb 5   0.40   0.64   0.41 no 1q81 A8113 Nb 6   0.32   0.50   0.73 no 1q81 A8102 Nb 2   0.31   0.08   0.81 no 1q81 A8098 Nb 4   0.23   0.66   0.83 no 1q81 A8046 Nb 3   0.17   0.31   0.98 no 1q81 A8075 2Or 5   0.49   0.46   0.80 no 1q81 A8097 2Ob 6   0.33   0.72   0.65 no 1q81 A8042 2Ob 6   0.33   0.44   0.49 no 1q81 A8011 2Nb 6   0.88   0.84   0.93 yes 1q81 A8117 2Or·Nb 6   0.34   0.70   0.25 no 1q81 A8050 Oph 3   0.24   0.18   0.59 no 1q81 A8103 Oph 2   0.36   0.14   0.95 no 1q81 A8090 Oph·Pout 3   0.30   0.18   0.54 no 1q81 A8084 Oph·Pout 6   0.48   0.70   0.36 no 1q81 A8083 Oph·Pout 6   0.85   0.88   0.89 yes 1q81 A8051 Oph·Pout 4   0.80   0.62   0.71 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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