PURIFICATION AND CHARACTERIZATION OF AN ENDO-EXONUCLEASE FROM ADULT FLIES OF DROSOPHILA-MELANOGASTER

被引:14
作者
SHUAI, K
DASGUPTA, CK
HAWLEY, RS
CHASE, JW
STONE, KL
WILLIAMS, KR
机构
[1] YESHIVA UNIV ALBERT EINSTEIN COLL MED,DEPT MOLEC BIOL & GENET,BRONX,NY 10461
[2] YALE UNIV,SCH MED,DEPT MOLEC BIOPHYS & BIOCHEM,NEW HAVEN,CT 06520
关键词
D O I
10.1093/nar/20.6.1379
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
An endo-exonuclease (designated nuclease III) has been purified to near homogeneity from adult flies of Drosophila melanogaster. The enzyme degrades single- and double-stranded DNA and RNA. It has a sedimentation co-efficient of 3.1S and a stokes radius of 27 angstrom The native form of the purified enzyme appears to be a monomer of 33,600 dalton. It has a pH optimum of 7-8.5 and requires Mg2+ or Mn2+ but not Ca2+ or Co2+ for its activity. The enzyme activity on double-stranded DNA was inhibited 50% by 30 mM NaCl, while its activity on single-stranded DNA required 100 mM NaCl for 50% inhibition. Under the latter conditions, its activity on double-stranded DNA was inhibited approximately 98%. The enzyme degrades DNA to complete acid soluble products which are a mixture of mono- and oligonucleotides with 5'-P and 3'-OH termini. Supercoiled DNA was converted by the enzyme to nicked and subsequently to linear forms in a stepwise fashion under the condition in which the enzyme works optimally on single-stranded DNA. The amino acid composition and amino acid sequencing of tryptic peptides from purified nuclease III is also reported.
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页码:1379 / 1385
页数:7
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