Table 4.

Comparison of CheY conformational signatures and pockets on signaling surface

Models	F432YZC(−)a	F432YZC(+)b	P2(1)2(1)2YZC(+)c	Actived	Inactivee	Apof
BeF3−(+/−)	−	+	+	+	−	−
M2+/H2O at active siteg	H2O	M2+	M2+	M2+	M2+
H2O
Active-site features
Coordination tetrahedral	tetrahedral	octahedral	octahedral	octahedral	octahedral
No. of ligands 4	4	6	6	6	6
M2+/H2O contact distancesg (Å)
57Asp Oσ	2.6	2.0	2.0	2.2	2.1
3.0
59Asn CO	2.8	2.2	2.1	2.3	2.2
2.8
13Asp Oσ	2.6	2.0	2.2	2.3	2.1
2.8
H2O # (range)h	1 (>3.0)	2 (2.1 – 2.3)	2 (2.1 – 2.2)	2 (2.4)	3 (2.1 – 2.2)
SO4 (2.8)
BeF3−	n/a	2.2	2.0	2.1	n/a
n/a
BeF3− contact distances (Å)
Be – 57Asp Oσ	n/a	1.6	1.7	1.5	n/a
n/a
F− – 59Asn NH	n/a	2.9	2.9	3.0	n/a
n/a
F− – 58Trp NH	n/a	3.2	3.2	2.9	n/a
n/a
F− – 88Ala NH	n/a	4.2/ 3.2i	2.9	2.9	n/a
n/a
F− – 109Lys Nζ	n/a	2.5	2.9	2.9	n/a
n/a
12Asp Oσ – H2O (Å)	2.9	2.7	2.6	2.6	2.2
2.8
109Lys Nζ – 12Asp Oσ (Å)	4.5	3.1	2.8	2.8	6.2
4.5
Naturej	indirect	direct	direct	direct	none
indirect
109Lys Nζ – 57Asp Oσ (Å)	2.8	3.3	3.3	3.3	5.0
2.7
57Asp χ1 (°)	−157	−177	−175	178	165
−151
109Lys χ4 (°)	−177	−176	173	172	37
−165
87Thr position
57Asp Oσ – 87Thr Oγ (Å)	6.9	6.9/ 4.2i	4.2	4.1	6.5	6.0
F− – 87Thr Oγ	n/a	5.2/ 2.6i	2.6	2.5	n/a	n/a
106Tyr features
106Tyr OH	87Thr Oγ/	87Thr Oγ/	89Glu NH	89Glu NH	n/a	87Thr
Oγ/
	94Asn Nσ	94Asn Nσ				94Asn
Nσ
Naturej	indirect	indirect	direct	direct	n/a
indirect
106Tyr conformation	buried	buried	buried	buried	exposed
dual
ϕ (°)	−147	−152	−155	−145	−136
−145
Ψ (°)	−52	−54	−60	−57	−31
−52
χ1 (°)	−178	−178	−155	−164	31
179/ 72k
χ2 (°)	−94	99	105	110	35
−71
Volume of α4-β4-α5 surface pockets (Å3)
α4-β5	−	−	12.0	15.7	285.0	−/
170.0k
β5-α5	55.5	61.5	119.1	96.0	−
35.0/ 40.0k

^aValues are given for the BeF₃⁻-free ^F432YZ_200-214 structure solved from a crystal grown in Tris (pH 8.4).

^bValues are given for the BeF₃⁻-bound ^F432YZ_200-214 structure solved from a crystal grown in Tris (pH 8.4).

^cValues are given for the BeF₃⁻-bound ^P2(1)2(1)2YZ_200-214 structure.

^dValues are given for BeF₃⁻-activated CheY¹⁵.

^eValues are given for inactive Mg²⁺-bound CheY¹⁴

^fValues are given for apoCheY¹³.

^gM²⁺ indicates a divalent cation

^hNumber of water molecules at the active site are indicated and the range of contact distances are given in parentheses.

ⁱValues correspond to “A” conformer/ “B” conformer of BeF₃⁻-bound ^F432YZ_200-214 (pH 8.4).

^jIndirect contacts are water or solvent-mediated hydrogen bonds; direct contacts are direct hydrogen bonds.