Coordination structures of Mg^<2+> and Ca^<2+> in three types of tobacco calmodulins in solution: Fourier-transform infrared spectroscopic studies of side-chain coo- groups
Coordination structures of Mg^<2+> and Ca^<2+> in three types of tobacco calmodulins in solution: Fourier-transform infrared spectroscopic studies of side-chain coo- groups
复制标题
溶液中三种烟草钙调蛋白中 Mg^<2> 和 Ca^<2> 的配位结构：侧链辅基的傅里叶变换红外光谱研究
DOI：
10.1002/bip.22203
复制
发表时间：
2013
期刊：
影响因子：
2.9
通讯作者：
and N. Yonezawa
中科院分区：
文献类型：
--
作者：
N. Suzuki;L. F. Imai;Y. Kato;K. Nagata;Y. Ohashi;K. Kuchitsu;M. Tanokura;A. Sakamoto;M. Nara;M. Nakano;and N. Yonezawa
钙调素（CaM）是一种钙离子结合蛋白，调节多种基本细胞活动，烟草CaM（NtCaM）由13个基因组成，分为3类，基因表达和靶酶激活各不相同。通过傅里叶变换红外光谱法，比较了作为3种NtCaMs的代表的NtCaM 1、NtCaM 3、NtCaM 13中的Mg 2+和Ca 2+的二级结构和配位结构。数据表明，由于β链带较弱和1661 cm-1带较弱，NtCaM 13具有不同的二级结构。NtCaM 3和NtCaM 13的Mg 2+配位结构与NtCaM 1相似但不同，而3种CaM的Ca 2 +-结合方式相似。由二阶导数光谱得到的1554-1550 cm− 1的带的振幅差表明，在低[Ca 2 +]条件下，NtCaM 13的带的强度响应于[Ca 2 +]增加的变化小于NtCaM 1和NtCaM 3的带的强度，而在高[Ca 2 +]条件下，强度达到相同水平。因此，NtCaM 13具有特征性的二级结构和特异性的Mg 2 +-结合方式，并且需要更高的[Ca 2 +]来进行EF-手型基序中第12个Glu的双齿Ca 2+配位。三种CaM的EF-手基序的Ca 2+结合机制相似;然而，NtCaM 13中的阳离子依赖性构象变化在三种NtCaM中是独特的。© 2013 Wiley Periodicals，Inc. Biopolymers 99：472-483，2013.
Calmodulin (CaM) is a Ca2+‐binding protein that regulates a number of fundamental cellular activities.Nicotiana tabacumCaM (NtCaM) comprises 13 genes classified into three types, among which gene expression and target enzyme activation differ. We performed Fourier‐transform infrared spectroscopy to compare the secondary and coordination structures of Mg2+and Ca2+among NtCaM1, NtCaM3, and NtCaM13 as representatives of the three types of NtCaMs. Data suggested that NtCaM13 has a different secondary structure due to the weak β‐strand bands and the weak 1661 cm−1band. Coordination structures of Mg2+of NtCaM3 and NtCaM13 were similar but different from that of NtCaM1, while the Ca2+‐binding manner was similar among the three CaMs. The amplitude differences of the band at 1554–1550 cm−1obtained by second‐derivative spectra indicated that the intensity change of the band of NtCaM13 was smaller in response to [Ca2+] increases under low [Ca2+] conditions than were those of NtCaM1 and NtCaM3, while the intensity reached the same level under high [Ca2+]. Therefore, NtCaM13 has a characteristic secondary structure and specific Mg2+‐binding manner and needs higher [Ca2+] for bidentate Ca2+coordination of 12th Glu in EF‐hand motifs. The Ca2+‐binding mechanisms of the EF‐hand motifs of the three CaMs are similar; however, the cation‐dependent conformational change in NtCaM13 is unique among the three NtCaMs. © 2013 Wiley Periodicals, Inc. Biopolymers 99: 472–483, 2013.