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 4tow 4TOW (2.9Å) -- RIBOSOME : Crystal structure of the e. coli ribosome bound to flopristin. this file contains the 30s subunit of the second 70s ribosome. List of all 56 Mg2+ binding sites in the PDB structure 4tow 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 3 | « Previous | Next » | 1 | 2 | 3

Mg2+ ion Site type Validation parameters PDB ID Mg2+ ID Coordination Number Qv # Qs # Qe # benchmark dataset 4tow A1648 Ob 1   0.02  0   0.54 no 4tow A1654 Ob 1   0.01  0   0.96 no 4tow A1633 Ob 5   0.67   0.67   0.78 yes 4tow A1638 Ob 6   0.87   0.90   0.85 yes 4tow A1611 Nb 6   0.82   0.83   0.67 yes 4tow A1609 Nb 6   0.82   0.82   0.86 yes 4tow A1625 2Nb 6   0.83   0.83   0.81 yes 4tow A1651 Oph 1   0.25  0   0.59 no 4tow A1628 Oph 6   0.85   0.87   0.91 yes 4tow A1650 Oph 1   0.12  0   0.81 no 4tow A1646 Oph 1   0.05  0   0.94 no 4tow A1644 Oph 1   0.05  0   0.64 no 4tow A1601 Oph 6   0.90   0.92   0.97 yes 4tow A1632 Oph 5   0.68   0.67   0.84 yes 4tow A1642 Oph 1   0.07  0   0.59 no 4tow A1602 Oph·Pout 6   0.92   0.96   0.82 yes 4tow A1627 Oph·Pout 6   0.83   0.86   0.80 yes 4tow A1616 Oph·Pout 6   0.87   0.87   0.97 yes 4tow A1610 Oph·Pout 6   0.84   0.85   0.86 yes 4tow A1626 Oph·2Pout 6   0.86   0.88   0.74 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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Developed by Heping Zheng and Ivan Shabalin at Minor lab (http://olenka.med.virginia.edu/CrystUVa/)
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