title: X-ray absorption microscopy of bacterial surface protein layers: X-ray damage.
abstract: The electronic structure of individual sheets of the bacterial surface protein layer (S layer) of Bacillus sphaericus NCTC 9602 was studied using a photoemission electron microscope (PEEM) operating in near-edge X-ray absorption fine structure spectroscopy mode. The laterally resolved measurements performed at the C 1s, N 1s, and O 1s thresholds on fresh samples revealed characteristic differences compared to the laterally integrated data, where substrate contributions were taken along with the protein signals. During the PEEM experiments an irradiation-induced increase of the C-C bond density at the cost of the densities of the C-O and C-N bonds related to a rearrangement of the contributing atoms of the S layer deposited onto a Si substrate was observed. The critical irradiation doses for the C-O and C-N bond breaking and formation of the new C-C bonds were derived.
authors.affiliation: Institute of Solid State Physics, Dresden University of Technology, D-01062 Dresden, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kade
authors.forename: Denis V
authors.initials: DV
authors.lastname: Vyalikh
authors.forename: Steffen
authors.initials: S
authors.lastname: Danzenbächer
authors.forename: Kurt
authors.initials: K
authors.lastname: Kummer
authors.forename: Anja
authors.initials: A
authors.lastname: Blüher
authors.forename: Michael
authors.initials: M
authors.lastname: Mertig
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lanzara
authors.forename: Andreas
authors.initials: A
authors.lastname: Scholl
authors.forename: Andrew
authors.initials: A
authors.lastname: Doran
authors.forename: Serguei L
authors.initials: SL
authors.lastname: Molodtsov
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000528:radiation effects; D008854:Microscopy, Electron / Q000379:methods*; D014965:X-Rays
chemical_list: D001426:Bacterial Proteins