ジャーナル: Nat Struct Mol Biol / 年: 2021 タイトル: Scaffolding protein CcmM directs multiprotein phase separation in β-carboxysome biogenesis. 著者: Kun Zang / Huping Wang / F Ulrich Hartl / Manajit Hayer-Hartl / 要旨: Carboxysomes in cyanobacteria enclose the enzymes Rubisco and carbonic anhydrase to optimize photosynthetic carbon fixation. Understanding carboxysome assembly has implications in agricultural ...Carboxysomes in cyanobacteria enclose the enzymes Rubisco and carbonic anhydrase to optimize photosynthetic carbon fixation. Understanding carboxysome assembly has implications in agricultural biotechnology. Here we analyzed the role of the scaffolding protein CcmM of the β-cyanobacterium Synechococcus elongatus PCC 7942 in sequestrating the hexadecameric Rubisco and the tetrameric carbonic anhydrase, CcaA. We find that the trimeric CcmM, consisting of γCAL oligomerization domains and linked small subunit-like (SSUL) modules, plays a central role in mediation of pre-carboxysome condensate formation through multivalent, cooperative interactions. The γCAL domains interact with the C-terminal tails of the CcaA subunits and additionally mediate a head-to-head association of CcmM trimers. Interestingly, SSUL modules, besides their known function in recruiting Rubisco, also participate in intermolecular interactions with the γCAL domains, providing further valency for network formation. Our findings reveal the mechanism by which CcmM functions as a central organizer of the pre-carboxysome multiprotein matrix, concentrating the core components Rubisco and CcaA before β-carboxysome shell formation.
解像度: 1.67→66.81 Å / Cor.coef. Fo:Fc: 0.976 / Cor.coef. Fo:Fc free: 0.965 / SU B: 3.55 / SU ML: 0.057 / 交差検証法: THROUGHOUT / σ(F): 0 / ESU R: 0.079 / ESU R Free: 0.083 / 立体化学のターゲット値: MAXIMUM LIKELIHOOD 詳細: HYDROGENS HAVE BEEN ADDED IN THE RIDING POSITIONS U VALUES : WITH TLS ADDED
Rfactor
反射数
%反射
Selection details
Rfree
0.1998
1173
4.9 %
RANDOM
Rwork
0.1637
-
-
-
obs
0.1656
22708
99.95 %
-
溶媒の処理
イオンプローブ半径: 0.8 Å / 減衰半径: 0.8 Å / VDWプローブ半径: 1.2 Å / 溶媒モデル: MASK