A probable aculeacin A acylase from the Ralstonia solanacearum GMI1000 is N-acyl-homoserine lactone acylase with quorum-quenching activity

Table 4 Substrate specificities of the AHL-acylase Aac against AHLs

	AHL-acylase activities (nmol·min^-1·ml^-1)^a
AHLs	E. coli DH10B (pBBR1MCS-3)	E. coli DH10B (pS3aac)
C4-HSL	0.26 ± 0.15 (7.2%)	0.37 ± 0.13 (10.3%)
C6-HSL	0.31 ± 0.15 (8.7%)	0.38 ± 0.10 (10.5%)
3OC6-HSL	0.37 ± 0.09 (10.5%)	0.35 ± 0.09 (10.5%)
C7-HSL	0.23 ± 0.15 (6.4%)	3.60 ± 0.31 (100.0%)*
C8-HSL	0.21 ± 0.16 (5.7%)	1.63 ± 0.21 (45.4%)*
3OC8-HSL	0.22 ± 0.17 (6.1%)	2.56 ± 0.04 (71.1%)*
C10-HSL	0.25 ± 0.15 (7.1%)	3.10 ± 0.25 (86.1%)*

^a Values represent the averages ± standard errors from triplicate independent HSL-OPA assays. The relative activity in parentheses is based on defining C7-HSL-degrading activity exhibited by E. coli DH10B (pS3aac) as 100%. The value with an asterisk (*) is the significant difference from the E. coli DH10B (pBBR1MCS-3) shown in the same row by one-tailed Student's t-test (P < 0.05)

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