Purification and characterization of an endo-exonuclease from adult flies of Drosophila melanogaster.
Purification and characterization of an endo-exonuclease from adult flies of Drosophila melanogaster.
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黑腹果蝇成年果蝇内切核酸酶的纯化和表征。
DOI：
10.1093/nar/20.6.1379
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发表时间：
1992
影响因子：
14.9
通讯作者：
Williams,KR
中科院分区：
文献类型：
--
作者：
Shuai,K;DasGupta,CK;Hawley,RS;Chase,JW;Stone,KL;Williams,KR
一种内切核酸外切酶（命名为核酸酶III）已从黑腹果蝇（Drosophila melanogaster）的成虫中纯化到接近同质。这种酶降解单链和双链DNA和RNA。其沉降系数为3.1S，斯托克斯半径为27。纯化酶的天然形式似乎是33，600道尔顿的单体。它的最适pH值为7 - 8.5，需要Mg 2+或Mn 2+，但不需要Ca 2+或Co2+。双链DNA上的酶活性被30 mM NaCl抑制50%，而其对单链DNA的活性需要100 mM NaCl才能抑制50%。在后一种条件下，其对双链DNA的活性被抑制约98%。该酶将DNA降解为完整的酸溶性产物，该产物是具有5′-P和3′-OH末端的单寡核苷酸和寡核苷酸的混合物。超螺旋DNA被酶转化为切口，随后在酶对单链DNA最佳作用的条件下以逐步的方式转化为线性形式。本文还报道了从纯化的核酸酶Ⅲ中分离的胰蛋白酶肽段的氨基酸组成和氨基酸序列。
An endo-exonuclease (designated nuclease III) has been purified to near homogeneity from adult flies ofDrosophila 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 27A 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 NaCI, while its activity on single-stranded DNA required 100 mM NaCI 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 peptldes from purified nuclease III is also reported.