FimH as a scaffold for regulated molecular recognition

Table 1 Effect of conformation on affinity of FimH for Penta-His

FimH Variant	Mutation(s)	Penta-His K_D (nM) w/o effector	Penta-His K_D (nM) with effector	Observed regulation by effectors	Effect of conformation on binding to Penta-His
CDR1-6XH-L	11–16➔6xH	170 ± 16^a	N/A		Higher affinity in tight conformation
CDR1-6XH-L	11–16➔6xH	114 ± 9^b	28 ± 3 man^b	activated
CDR1-6XH-T	11–16➔6xH A188D	38 ± 4^a	32 ± 3 mab21^a	no effect
CDR1-6XH-T	11–16➔6xH A188D	34 ± 3^b	13 ± 1 man^b	activated
CDR2-6xH-L	47–53➔6xH	7.5 ± 0.4^a	N/A		Higher affinity in loose conformation
CDR2-6xH-L	47–53➔6xH	N/A	N/A
CDR2-6xH-T	47–53➔6xH A188D/Y64R	21 ± 1^a	51 ± 3 mab21^a	inhibited
CDR2-6xH-T	47–53➔6xH A188D/Y64R	40 ± 9^b	120 ± 20 man^b	inhibited
CDR3-6xH-L	135–140➔6xH	2.8 ± 0.3^a	N/A		No effect of conformation on affinity
CDR3-6xH-L	135–140➔6xH	N/A	N/A
CDR3-6xH-T	135–140➔6xH A188D/Y64R	3.6 ± 0.2^a	3.7 ± 0.2 mab21^a	no effect
CDR3-6xH-T	135–140➔6xH A188D/Y64R	N/A	N/A

^a Affinity for Penta-His determined in Fig. 3 (with or without mab21)
^b Affinity for Penta-His determined in Fig. 5 (with or without man (mannose))
N/A indicates that this was not applicable because the CDR-6xH variant did not bind the effector in question (mab21 binding determined in Fig. 1 and mannose-binding determined in Fig. 4)

ISSN: 1754-1611