TY  - THES
AB  - Azotobacter vinelandii is a diazotrophic soil-dwelling bacterium distinguished from other diazotrophs by its capability of storing Mo in a special storage protein which ensures Mo-dependent nitrogen fixation even under conditions of extreme Mo scarcity. By an improved purification protocol based on methods from earlier publications, this storage protein was isolated as an [alpha]4[beta]4-octamer with subunit masses of 28.2 and 29.2 kg/mol and a total molecular mass of 230 kg/mol. The genes of the [alpha] and [beta] subunits were identified, their amino acid sequences reveal that the Mo storage protein is not related to any other known molybdoprotein. On the other hand it is likely that a similar hitherto unrecognised storage protein occurs in Rhodopseudomonas palustris. Putative features of the three-dimensional structure were deduced from the amino acid sequence. The protein shape was determined by small-angle X-ray scattering.
Each protein molecule can store at least 90 Mo atoms. Extended X-ray absorption fine structure spectroscopy (EXAFS) identified a heptamolybdate-related molybdenum-oxygen cluster bound to the Mo storage protein. According to its amino acid sequence as well as to the structure of its Mo component the Mo storage protein represents a novel type of molybdoprotein.
The experimental results are put into context by a brief review of the most closely related fields of science, focussed on biological metal storage, characteristics of molybdate(VI)-binding proteins, and the chemistry of molybdate(VI) in aqueous solutions.
DA  - 2004
KW  - Azotobacter vinelandii , Reserveproteine , Metallproteide , Mangankomplexe , EXAFS , Metallspeicherung , Molybdän , Polymolybdate , Molybdoprotein , Speicherprotein , Molybdenum , Storage protein , Metal storage
LA  - ger
PY  - 2004
TI  - Das Molybdän-Speicherprotein von Azotobacter vinelandii : grundlegende Untersuchungen an einem neuartigen Metalloprotein
UR  - https://nbn-resolving.org/urn:nbn:de:hbz:361-7375
Y2  - 2024-11-22T03:45:02
ER  -