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In this work, long‐term antibacterial, antiadhesion, and antibiofilm activities are afforded to industrial stainless steel surfaces following a green and bio‐inspired strategy. Starting from catechol bearing synthetic polymers, the film cross‐linking and the grafting of active (bio)molecules are possible under environmentally friendly conditions (in aqueous media and at room temperature). A bio‐inspired polyelectrolyte, a polycation‐bearing catechol, is used as the film‐anchoring polymer while a poly(methacrylamide)‐bearing quinone groups serves as the cross‐linking agent in combination with a polymer bearing primary amine groups. The amine/quinone reaction is exploited to prepare stable solutions of nanogels in water at room temperature that can be easily deposited to stainless steel. This coating provides quinone‐functionalized surfaces that are then used to covalently anchor active (bio)molecules (antibiofilm enzyme and antiadhesion polymer) through thiol/quinone reactions.

The noncovalent complexes between the BlaI protein dimer (wild type and GM2 mutant) and its double-stranded DNA operator were studied by nanospray mass spectrometry and MS/MS. Reproducibility problems in the nanospray single-stage MS are emphasized. The relative intensities depend greatly on the shape of the capillary tip, and on the capillary-cone distance. This results in difficulties in assessing the relative stabilities of the complexes simply from MS spectra of protein-DNA mixtures. Competition experiments are a better approach to determine relative binding affinities. A competition between histidine-tagged BlaIWT (BlaIWTHis) and the GM2 mutant revealed that the two proteins have similar affinities for the DNA operator, and that they co-dimerize to form heterocomplexes. The low sample consumption of nanospray allows MS/MS spectra to be recorded at different collision energies for different charge states with 1 µL of sample. The MS/MS experiments on the dimers reveals that the GM2 dimer is more kinetically stable in the gas phase than the wild type dimer. The MS/MS experiments on the complexes shows that the two proteins require the same collision energy to dissociate from the complex. This indicates that the rate-limiting step in the monomer loss from the protein-DNA complex arises from the breaking of the protein-DNA interface rather than the protein-protein interface. The dissociation of the protein-DNA complex proceeds by the loss of a highly charged monomer (carrying about two thirds of the total charge and one third of the total mass). MS/MS experiments on a heterocomplex also show that the two proteins BlaIWTHis and BlaIGM2 have slightly different charge distributions in the fragments. This emphasizes the need for better understanding the dissociation mechanisms of biomolecular complexes.

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