Rahman Suhaila, Yamato Ichiro, Saijo Shinya, Mizutani Kenji, Takamuku Yuuki, Ishizuka-Katsura Yoshiko, Ohsawa Noboru, Terada Takaho, Shirouzu Mikako, Yokoyama Shigeyuki, Murata Takeshi
a Department of Biological Science and Technology , Tokyo University of Science , Tokyo , Japan.
b Department of Chemistry , Graduate School of Science, Chiba University , Chiba , Japan.
Biosci Biotechnol Biochem. 2016 May;80(5):878-90. doi: 10.1080/09168451.2015.1135043. Epub 2016 Feb 10.
The mammalian peripheral stalk subunits of the vacuolar-type H(+)-ATPases (V-ATPases) possess several isoforms (C1, C2, E1, E2, G1, G2, G3, a1, a2, a3, and a4), which may play significant role in regulating ATPase assembly and disassembly in different tissues. To better understand the structure and function of V-ATPase, we expressed and purified several isoforms of the human V-ATPase peripheral stalk: E1G1, E1G2, E1G3, E2G1, E2G2, E2G3, C1, C2, H, a1NT, and a2NT. Here, we investigated and characterized the isoforms of the peripheral stalk region of human V-ATPase with respect to their affinity and kinetics in different combination. We found that different isoforms interacted in a similar manner with the isoforms of other subunits. The differences in binding affinities among isoforms were minor from our in vitro studies. However, such minor differences from the binding interaction among isoforms might provide valuable information for the future structural-functional studies of this holoenzyme.
液泡型H(+)-ATP酶（V-ATP酶）的哺乳动物外周柄亚基有几种同工型（C1、C2、E1、E2、G1、G2、G3、a1、a2、a3和a4），它们可能在不同组织中调节ATP酶的组装和拆卸过程中发挥重要作用。为了更好地理解V-ATP酶的结构和功能，我们表达并纯化了人V-ATP酶外周柄的几种同工型：E1G1、E1G2、E1G3、E2G1、E2G2、E2G3、C1、C2、H、a1NT和a2NT。在此，我们研究并表征了人V-ATP酶外周柄区域同工型在不同组合下的亲和力和动力学。我们发现不同的同工型与其他亚基的同工型以相似的方式相互作用。从我们的体外研究来看，同工型之间结合亲和力的差异很小。然而，同工型之间结合相互作用的这种微小差异可能为该全酶未来的结构-功能研究提供有价值的信息。
