Table 2.

DLS analysis of LbPrx1m pretreated with several divalent cations

Samples were pretreated with several divalent cations (at 20 mm) in 25 mm Tris-HCl (pH 7.5) and 5 mm EDTA. Note that only the additives CaCl₂ and MgCl₂ led to a monodisperse protein size distribution (Pd < 20%) in which most of the enzyme population (≥80% mass) displayed an average R_H (∼6 nm) compatible with the decameric structure (R_G = 5 nm). Zn²⁺, in particular, induced the formation of larger aggregates besides the species of R_H ∼ 9 nm, probably because of non-specific interactions with the enzyme.

Salt	RH	Pda	Mass
	nm	%	%
CaCl2	5.9	8.0	90
MgCl2	5.6	10.1	80
NiCl2	6.0	30.9	55
FeCl2	4.6	29.3	50
MnCl2	4.6	86.4	25
ZnCl2	9.2	11.9	10

^a Pd, polydispersity.