. 2005 Aug 16;33(14):4649–4659. doi: 10.1093/nar/gki782

Table 2.

Sedimentation values for known and alternative K⁺ structures

	Overall fold^a	Rotation of fold^b	Quartet rotation^c	Loop orientation^d	Energy (kJ/mol)	Sedimentation value^e
X-ray	Parallel	Right	Clockwise	Propeller	−18 940^f (−18 914^g)	1.72^f (1.69^g)
NMR	Antiparallel	Right	Alternating	Basket	−19 279^h (−19 057ⁱ)	1.92^h (1.89ⁱ)
A	Antiparallel	Right	Clockwise	Basket	−19 248	1.88
B	Antiparallel	Left	Alternating	Chair	−19 201	1.86
C	Antiparallel	Right	Clockwise	Chair	−19 239	1.86
D	Antiparallel	Right	Anticlockwise	Basket	−19 177	1.86
E	Antiparallel	Right	Alternating	Chair	−19 095	1.83
F	Antiparallel	Left	Clockwise	Chair	−19 119	1.81
G	Antiparallel	Right	Alternating	Mixed	−19 093	1.80

^aParallel: the four backbone regions of guanines are in the same 5′ to 3′ direction. Antiparallel: the four backbone regions of guanines are in the different 5′ to 3′ directions.

^bTopological rotation of the direction of the strands, right- or left-handed defined by the position of the second quanine bases forming the G-quartet with respect to the 5′-AGGG position.

^cThe rotational direction of the bases within the G-quartets. Clockwise has all three quartets with the bases in the same clockwise rotation as in the crystal structure. Anticlockwise has all three quartets with the bases in the same anticlockwise rotation opposite to that in the crystal structure. Alternating has the three quartets in the same rotational orientation as in the NMR structure.

^dLocation of the loops. Propeller: loops running exteriorly to the G-quartets; Basket: as in the NMR structure with a second loop being positioned diagonally across the G-quartets; Chair: all loops being lateral; Mixed: the first and second loops are lateral with the third loop in the propeller orientation

^eCalculated in HYDROPRO.

^fReported X-ray crystal structure optimized by molecular dynamics.

^gReported X-ray crystal structure, no molecular dynamics optimization.

^hAntiparallel NMR structure optimized by molecular dynamics with K⁺ ions.

ⁱAntiparallel NMR structure with K⁺ ions in Na+ positions with minimization but no molecular dynamics optimization.