BIAŁKA PODZIAŁU KOMÓRKOWEGO BAKTERII
- DRUŻYNA PIERŚCIENIA
Marta Popławska1,2, Jarosław
Dziadek2
1Uniwersytet Łódzki, ul. Banacha 12/16, 93-237 Łódź,
e-mail: mborun@cbm.pan.pl, tel. (42) 635 45 00
2Centrum Biologii Medycznej, Polska Akademia Nauk, ul. Lodowa 106, 93-232 Łódź,
e-mail: jdziadek@cbm.pan.pl, tel. (42) 272 36 10
Wpłynęło we wrześniu 2006 r.
1. Główne białko zaangażowane w proces podziału komórkowego -
FtsZ. 2. Regulacja tworzenia pierścienia Z. 3. Inne białka zaangażowane w tworzenie przegrody międzykomórkowej i proces podziału komórkowego. 4. Proces podziału komórkowego
drobnoustrojów z rodzaju Mycobacterium
Bacterial cell division proteins. The fellowship of the ring
Abstract: Cell division in bacteria takes place at the midcell and occurs after DNA has been duplicated and segregated into two nucleoids. The division process starts with the localization of FtsZ at the center of the cell and formation of a septal ring structure called Z-ring. Once the septum is fully formed, the Z-ring disappears and the daughter cells separate. An ordered assembly of other proteins follows this process (eg. FtsA, ZipA, FtsK, FtsQ, FtsL, FtsB, FtsW, FtsI, FtsN).
FtsZ is a highly conserved protein that is found in most of the major groups of bacteria. FtsZ is a structural homolog of tubulin; like tubulin, purified FtsZ binds and hydrolyses GTP and assembles in vitro into filaments, sheets and other structures.
One important inhibitory system, the Min system, is crucial for the precise positioning of the Z-ring. In E. coli this system consist of the FtsZ assembly inhibitor, MinC protein, and the MinD and MinE proteins which move from one cell pole to the other. Because MinC is associated with the relocating MinD protein, FtsZ assembly is inhibited at the cell poles. Another important regulatory system is nucleoid occlusion. Like Min system, nucleoid occlusion negatively regulates Z-ring assembly. Acting independently of the Min system nucleoid occlusion prevents the assembly of the Z ring on top of unreplicated chromosomal DNA. Several positive and negative regulators of Z ring assembly are known eg. ZipA, EzrA, ClpX, SulA, Noc proteins.
The lack of FtsA, ZipA and FtsN cell division proteins suggests that the mechanisms of cell division are likely to be different in Mycobacterium as compared with
E. coli. FtsZ and FtsQ are essential cell division proteins in Mycobacterium smegmatis and
M. tuberculosis. The C-termini ofM. tuberculosis FtsZ and FtsW carries a string of amino acid residues that are absent in their
E. coli counterparts. FtsZ and FtsW of M. tuberculosis are binding partners and that binding involves a cluster of aspartate residues
in the C-tail of FtsZ.
1. The main cell division protein - Fts 2. Regulation of the Z-ring localization 3. Other cell division proteins 4. Cell division process in
Mycobacterium sp.
Słowa kluczowe: białko FtsZ, białka podziału komórkowego,
Mycobacterium,
podział komórki bakteryjnej
Key words: FtsZ protein, Mycobacterium sp., cell division process
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