TABLE 1.

Hydrogen bonds between the antigenic peptide A15 and the Fab fragment in complexes between A15 and 4C4 or SD6^a

MAb	Bond interaction site in:		Location	Distance (Å)
	FMDV C-S8c1 peptide	MAb Fab fragment
4C4	Thr137 N	Arg54 Nη2	L2	2.6
	Thr137 O	Asp104 N	H3	3.2
	Thr137 Oγ1	Asp34 Nδ2	L1	2.9
	Ser139 Oγ	Asn96 Oδ1	L3	3.4
	Asp143 O	Tyr59 Oη	H2	3.4
	Asp143 Oδ1	Arg9 Nη2	H3	2.7
	Asp143 Oδ2	Arg99 Nη1	H3	2.8
	Asp143 Oδ2	Thr50 Oγ1	H2	3.0
	His146 Nδ1	Tyr59 Oη	H2	2.6
	His146 Nδ2	Thr33 Oγ	H1	3.2
	His146 Nδ2	Ser52 Oγ	H2	2.8
SD6	Tyr136 Oη	Glu100 Oɛ2	H3	2.6
	Tyr136 Oη	Gly103 N	H3	3.2
	Thr137 O	Asp104 N	H3	2.7
	Ser139 Oγ	Ser31 Oγ	L1	3.2
	Ser139 Oγ	Asn96 Oδ1	L3	3.3
	Arg141 O	Glu97 N	L3	2.6
	Arg141 Nɛ	Glu97 Oɛ1	L3	3.1
	Asp143 O	Tyr59 Oη	H2	3.4
	Asp143 Oδ1	Arg99 Nη2	H3	3.3
	Asp143 Oδ2	Arg99 Nη1	H3	3.2
	Asp143 Oδ2	Thr50 Oγ1	H2	2.6
	His146 Nδ1	Tyr59 Oη	H2	2.7
	His146 Nδ2	Ser52 Oγ	H2	3.2
	His146 Nδ2	Ser53 Oγ	H2	2.8

^aProcedures for structure determination are detailed in Materials and Methods. The amino acid sequences of antigenic peptide A15 and of the variable regions of MAbs 4C4 and SD6 are given in Fig. 1.