The high-resolution NMR structure of the R21A Spc-SH3:P41 complex: Understanding the determinants of binding affinity by comparison with Abl-SH3

Table 4 Intermolecular contacts¹ statistics calculated over the ensemble of twenty R21A Spc-SH3:P41 complex structures.

Interacting residues		Hydrogen bonds			Non-bonded contacts	Occurrence Total	Interacting residue in Abl-SH3
p41	Spc-SH3	M-M	S-S	M-S		%
Ace0	Phe52	0	0	0	2	70	Trp47 (2, 75%)
Ala1	Phe52	0	0	0	3	95	Trp47 (6, 100%)
Pro2	Trp41	0	0	0	7	100	Trp36 (2, 100%)
Pro2	Phe52	0	0	0	2	50	Trp47 (2, 50%)
Tyr4	Lys18	0	1	0	0	100	Ser12 (0, 75%)
Tyr4	Trp41	0	0	0	1	95	Trp36 (1, 75%)
Tyr4	Trp41	0	0	1	0	100	Trp36 (0, 100%)
Pro6	Pro54	0	0	0	1	70	Pro49 (2, 100%)
Pro6	Asp40	0	0	0	2	100	Glu35 (2, 50%)
Pro6	Trp41	0	0	0	3	100	Trp36 (5, 100%)
Pro7	Tyr15	0	0	0	1	80	Phe9 (2, 100%)
Pro8	Tyr57	0	0	1	0	15	Tyr52 (0, 100%)
Pro9	Tyr13	0	0	0	2	100	Tyr7 (2, 100%)
Pro9	Tyr57	0	0	0	3	100	Tyr52 (1, 100%)
Pro10	Tyr13	0	0	0	2	65	Tyr7 (7, 100%)
Pro10	Tyr57	0	0	0	1	40	Tyr52 (1, 75%)
Pro7	Tyr57	0	0	1	0	95	-
Ala1	-	0	0	0	-	-	Asn31 (1, 100%)
Ala1	-	0	0	0	-	-	Trp36 (1, 75%)
Pro2	-	0	0	0	-	-	Thr16 (1, 100%)
Tyr4	-	0	1	0	-	-	Asp14 (1, 75%)
Ser5	-	0	0	0	-	-	Trp36 (1, 50%)

¹Intermolecular contacts were analyzed with LIGPLOT [24] using the default settings: 2.7Å and 3.35Å proton-acceptor and donor-acceptor distance cut-offs, respectively with minimum 90° angles for hydrogen bonds; 3.9Å heavy atom pair distance cut-off for non-bonded contacts. Contacts are reported if present in at least 10 of the 20 structures or in at least 1 of the 20 structures when the corresponding contact in Abl-SH3 is present in 2 or more of the 4 models in the pdb entry 1BBZ. Hydrogen bonds are reported for main-chain to main-chain (M-M), side-chain to side-chain (S-S) and main-chain to side-chain (M-S). The average number of non-bonded contacts is reported, as well as the percentage of occurrences of a contact. The corresponding interacting residue in Abl-SH3 for a certain contact and the number of contacts and occurrence in the 4 models (between brackets, respectively) are given in the last column. The last five rows correspond to contacts present in Abl-SH3:P41 that are not present in any of the 20 structures reported here.

ISSN: 1472-6807