Table 3.

Xanthophyll spectral forms and efficiency of energy transfer to Chl a in LHCII monomeric preparations purified by non-denaturing IEF from WT and lut2.1 thylakoids.

		Site
		L1	L2		N1
LHCII WT	Spectral form	Lutein1 (489 nm)	Lutein2 (495 nm)	Viola1 (492 nm)	Neoxanthin (486.5 nm)
	Efficiency	81.0%	79.0%		60.0%
LHCII lut2.1	Spectral form	Viola2 (505 nm)		Viola1 (493.5 nm)	Neoxanthin (486.5 nm)
	Efficiency	93.8%		79.0%	60.0%

Spectral deconvolution analysis and calculation of energy transfer efficiency were as in Croce et al.,, 1999 [18]. The data, normalized to the WT, are relative to a 100% Chl a-to-Chl a ET efficiency. The error in the ET efficiency was <4%, with the exception of Viola1 in WT (>10%). Xanthophyll absorption maxima in ethanol are 477.2, 472.8 and 468.4 nm, respectively, for violaxanthin, lutein and neoxanthin. Binding to sites L2 and L1 shifts violaxanthin absorption from 477.2 to 492 and 505 nm respectively; lutein is shifted from 472.8 to 489 and 495 nm, respectively. Binding to site N1 shifts neoxanthin from 468.4 to 486.5 nm.