Direct Covalent Biomolecule Immobilization on Plasma-Nanotextured Chemically Stable Substrates.

A new method for direct covalent immobilization of protein molecules (including antibodies) on organic polymers with plasma-induced random micronanoscale topography and stable-in-time chemical functionality is presented. This is achieved using a short (1-5 min) plasma etching and simultaneous micronanotexturing process, followed by a fast thermal annealing step, which induces accelerated hydrophobic recovery while preserving important chemical functionality created by the plasma. Surface-bound biomolecules resist harsh washing with sodium dodecyl sulfate and other detergents even at elevated temperatures, losing less than 40% of the biomolecules bound even at the harshest washing conditions.

Can we trap the S(3)Y(Z)· metalloradical intermediate during the S-state transitions of Photosystem II? An EPR investigation.

We report the trapping of two metalloradical intermediates corresponding to the transitions S2 to S3 and S3 to S0 of the oxygen evolving complex (OEC) of Photosystem II (PSII), in preparations containing methanol, at temperatures near that of half inhibition of the respective S-state transitions. The first intermediate, with an EPR width of 160 G, is assigned to S2YZ, based on its similarity to the one previously characterized after trapping at 10 K. The second with a splitting of ∼80 G is tentatively assigned to S3YZ.

Conformational changes of the S2YZ* intermediate of the S2 to S3 transition in photosystem II.

The paper extends earlier studies on the S(2)Y(Z)* intermediate that is trapped by illumination in the temperature range 77 K to 190 K of untreated samples poised in the S(2)...

Conversion of the g=4.1 EPR signal to the multiline conformation during the S(2) to S(3) transition of the oxygen evolving complex of Photosystem II.

The oxygen evolving complex of Photosystem II undergoes four light-induced oxidation transitions, S(0)-S(1),...

The EPR spectrum of tyrosine Z* and its decay kinetics in O2-evolving photosystem II preparations.

The O2-evolving complex of photosystem II, Mn 4Ca, cycles through five oxidation states, S0,...