Synthetic CO2-fixation enzyme cascades immobilized on self-assembled nanostructures that enhance CO2/O2 selectivity of RubisCO

Table 3 Catalytic properties of RubisCO enzymes (R. eutropha form I (FI) and R. rubrum form II (FII) associated with nanostructures

Enzyme^a	Ω ^b (V _c K _o/V _o K _c)	k ^b_cat (sec⁻¹)	K ^b_c (μM)	K ^b_o (μM)	K _o/K ^c_c
Unbound FI	79 ± 1	2.6 ± 0.5	41 ± 4	1093 ± 141	27
FI-nanotube B	95 ± 3^d	1.8 ± 0.1^e	53 ± 7	1756 ± 341	33
FI-nanofiber C	88 ± 1^d	2.2 ± 0.1^e	56 ± 8	1693 ± 383	30
Unbound FII	17 ± 2	1.2 ± 0.1	100 ± 7	96 ± 26	1.0
FII-nanotube B	17 ± 1	0.6 ± 0.2^e	120 ± 24	170 ± 41	1.4
FII in nanofiber C	17 ± 1	0.6 ± 0.1^e	96 ± 16	95 ± 32	1.0

^aAssociation with either of the nanotubes (i.e., A or B) imparted similar properties to both form I (FI) and form II (FII) enzymes
^bValues are the mean ± standard deviation (n−1) of at least three independent nanostructure-enzyme complex preparations
^cCalculated values
^dAn unpaired t test with Ω values obtained from three independent experiments gave p values of 0.0006 and 0.0003 for FI-nanotube B and FI-nanofiber C, respectively, relative to unbound FI
^eThese k _cat values were calculated based on the initial amounts of enzyme added to constitute nanostructure-RubisCO complexes. They are not significantly different from the value measured with the unbound enzyme, if the percentage recoveries are factored into the calculations (Additional file 1: Table S3c) for each experiment

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