Abstract |
DNA (cytosine-5-)-methyltransferase was purified as a single polypeptide (190 kDa by SDS-PAGE) from mouse P815 mastocytoma cells. This enzyme transfers methyl groups to unmethylated as well as to hemimethylated DNA sites with a strong preference for the hemimethylated substrate. A structural analysis of the isolated enzyme by electron microscopical techniques was undertaken. On the basis of the results obtained, we propose a model for the enzyme structure. This model describes the enzyme as a hemi-elliptical globular structure with dimensions of 5.4-6.7 nm for the height h and 10.3-10.8 nm for the diameter d, respectively; this globular structure bears a small appendix at the flat side. A molecular mass of 235-250 kDa is calculated from the measured dimensions. Limited trypsin digestion of the enzyme led to a 160-kDa fragment which preserved the gross morphology of the original material. The possible structure function relationships are discussed.
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Authors | E Spiess, A Tomassetti, P Hernaiz-Driever, G P Pfeifer |
Journal | European journal of biochemistry
(Eur J Biochem)
Vol. 177
Issue 1
Pg. 29-34
(Oct 15 1988)
ISSN: 0014-2956 [Print] England |
PMID | 3141151
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- DNA (Cytosine-5-)-Methyltransferases
- Trypsin
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Topics |
- Animals
- DNA (Cytosine-5-)-Methyltransferases
(analysis)
- Freeze Drying
- Mast-Cell Sarcoma
(enzymology)
- Mice
- Microscopy, Electron
- Models, Chemical
- Models, Molecular
- Structure-Activity Relationship
- Trypsin
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