Table 1 Oligomeric states, thermostability and enzyme activity of wild-type NylC and mutant enzymes.

Enzyme	Amino acid substitutions in NylC_p2 sequence	Oligomeric state*¹	Subunit identified by SDS-PAGE	CD-melting analysis*² T_m (°C)	Enzyme activity*³ (U mg⁻¹)
NylC_p2	—	Trimer/Dimer (Monomer)	α, β	52	7.1
NylC_A	G111S D122G H130Y L137A V225M	Tetramer	α, β	60	15.7
NylC_K	D36A A41V M50T I60V A62S G111S D122G H130Y L137A V225M T230G V231I V257L E263Q G354A	Tetramer (Monomer, Higher oligomer)	α, β	67	14.9
NylC_p2-Y¹³⁰	H130Y	Not tested	α, β	63	0.85
A¹³⁷	L137A	Dimer (Monomer, Higher oligomer)	Precursor	41	< 0.1
G¹²²Y¹³⁰	D122G H130Y	Not tested	α, β	81	7.1
G¹²²A¹³⁷	D122G L137A	Dimer or monomer (Trimer)	Mixture of α, β, precursor	Not tested	Not tested
G¹²²Y¹³⁰A³⁶Q²⁶³	D122G H130Y D36A E263Q	Tetramer (Monomer)	α, β	88	6.8

^*1Oligomeric states of NylC in aqueous solution were estimated from analytical centrifugation. Minor populations are shown in parentheses. For example, in wild-type NylC_p2, trimeric and dimeric αβ heterodimers were found at equal amounts, while a small population was present as monomeric αβ heterodimer. In NylC_p2-A¹³⁷, uncleaved dimeric molecules share the dominant population.
^*2The thermostability determined previously by CD melting analysis (ref.⁹) is shown.
^*3The enzyme activity was assayed at 30 °C under standard assay conditions (4 mg ml⁻¹ of the cyclic Ahx oligomer) (ref.⁹).

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