首页> 外文OA文献 >A tobacco (Nicotiana tabaccum) calmodulin-binding protein kinase, NtCBK2, is regulated differentially by calmodulin isoforms.
【2h】

A tobacco (Nicotiana tabaccum) calmodulin-binding protein kinase, NtCBK2, is regulated differentially by calmodulin isoforms.

机译:烟草钙调蛋白结合蛋白激酶NtCBK2受钙调蛋白同工型差异调节。

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

A calcium (Ca2+)/calmodulin (CaM)-binding protein kinase (CBK) from tobacco (Nicotiana tabaccum ), NtCBK2, has been characterized molecularly and biochemically. NtCBK2 has all 11 conserved subdomains of the kinase-catalytic domain and a CaM-binding site as shown by other kinases, including Ca2+-dependent protein kinase and chimaeric Ca2+/CaM-dependent protein kinases. However, this kinase does not contain an EF-hand motif for Ca2+ binding, and its activity was not regulated by Ca2+. Whereas NtCBK2 phosphorylated both itself and other substrates, such as histone IIIS and syntide-2, in a Ca2+/CaM-independent manner, as also shown by OsCBK, a CaM-binding protein kinase from rice (Oryza sativa ), the kinase activity of NtCBK2 was greatly stimulated by Ca2+/CaM, whereas that of OsCBK was not. By molecular dissection analyses, the CaM-binding domain of NtCBK2 has been localized in a stretch of 30 amino acid residues at residue positions 431-460 as a 1-5-10 protein motif. Three tobacco CaM isoforms (NtCaM1, NtCaM3 and NtCaM13) used in the present study have been shown to bind to NtCBK2, but with different dissociation constants ( K(d)s), as follows: NtCaM1, 55.7 nM; NtCaM3, 25.4 nM; and NtCaM13, 19.8 nM, indicating that NtCBK2 has a higher affinity for NtCaM3 and NtCaM13 than for NtCaM1. The enzymic activity of NtCBK2 was also modulated differently by various CaM isoforms. Whereas the phosphorylation activity of NtCBK2 was shown by assay to be enhanced only approximately 2-3-fold by the presence of NtCaM1, the activity could be amplified up to 8-9-fold by NtCaM3 or 10-11-fold by NtCaM13, suggesting that NtCaM3 and NtCaM13 are better activators than NtCaM1 for NtCBK2.
机译:烟草(Nicotiana tabaccum)的钙(Ca2 +)/钙调蛋白(CaM)结合蛋白激酶(CBK)NtCBK2的分子和生化特性已得到表征。 NtCBK2具有激酶催化结构域的所有11个保守亚结构域和一个CaM结合位点,如其他激酶所示,包括Ca2 +依赖性蛋白激酶和Chimaeric Ca2 + / CaM依赖性蛋白激酶。但是,该激酶不包含用于Ca2 +结合的EF手基序,并且其活性不受Ca2 +的调节。 NtCBK2自身和其他底物(例如组蛋白IIIS和syntide-2)都以Ca2 + / CaM依赖性方式被磷酸化,正如OsCBK(一种来自水稻(Oryza sativa)的CaM结合蛋白激酶)所示, NtCBK2受到Ca2 + / CaM的极大刺激,而OsCBK则没有。通过分子解剖分析,NtCBK2的CaM结合域已定位在30个氨基酸残基的延伸中,位于残基位置431-460处,为1-5-10蛋白基序。已显示本研究中使用的三种烟草CaM亚型(NtCaM1,NtCaM3和NtCaM13)与NtCBK2结合,但具有不同的解离常数(K(d)s),如下所示:NtCaM1,55.7 nM; NtCaM1,55.7 nM。 NtCaM3,25.4 nM; NtCaM13为19.8 nM,表明NtCBK2对NtCaM3和NtCaM13的亲和力高于对NtCaM1的亲和力。 NtCBK2的酶活性也受到各种CaM亚型的调节。通过分析显示,NtCBK2的磷酸化活性仅在存在NtCaM1的情况下增强了约2-3-倍,而NtCaM3可以将其活性扩增到8-9倍,NtCaM13可以将其扩增到10-11-倍。 NtCaM3和NtCaM13是比NtCBK2更好的激活剂。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
代理获取

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号