TY - JOUR
T1 - Metal-ion-induced formation and stabilization of protein cages based on the cowpea chlorotic mottle virus
AU - Minten, I.J.
AU - Wilke, K.D.M.
AU - Hendriks, L.J.A.
AU - van Hest, J.C.M.
AU - Nolte, R.J.M.
AU - Cornelissen, J.J.L.M.
PY - 2011/4/4
Y1 - 2011/4/4
N2 - The cowpea chlorotic mottle virus (CCMV) is a versatile building block for the construction of nanoreactors and functional materials. Upon RNA removal, the capsid can be reversibly assembled and disassembed by adjusting the pH. At pH 5.0 the capsid is in the native assembled conformation, while at pH 7.5 it disassembles into 90 capsid protein dimers. This special property enables the encapsulation of various molecules, such as protein and enzymes, but only at low pH. It is possible to stabilize the capsid at pH 7.5 by addition of negatively charged polyelectrolytes or negatively charged particles, but these methods all fill the interior of the capsid, leaving little or no space for other cargo molecules. This pH restriction therefore severely limits the range of enzymes that can be encapsulated, and hampers the investigation of the CCMV capsid as a nanoreactor for the study of enzymes in confined spaces. Herein, the interaction of N-terminal histidine-tag-modified capsid proteins with several metal ions is reported. Depending on the conditions used, nanometer-sized protein particles or capsidlike architectures are formed that are stable at pH 7.5. This metal-mediated stabilization methodology is employed to form stable capsids containing multiple proteins at pH 7.5, thereby greatly expanding the scope of the CCMV capsid as a nanoreactor. The cowpea chlorotic mottle virus capsid, devoid of RNA, is stable at pH 5.0 but disassembles into dimers at pH 7.5. Capsid proteins modified with an N-terminal histidine tag can be stabilized at pH 7.5 by the addition of nickel ions to the assembled capsids at pH 5.0, followed by dialysis to pH 7.5.
AB - The cowpea chlorotic mottle virus (CCMV) is a versatile building block for the construction of nanoreactors and functional materials. Upon RNA removal, the capsid can be reversibly assembled and disassembed by adjusting the pH. At pH 5.0 the capsid is in the native assembled conformation, while at pH 7.5 it disassembles into 90 capsid protein dimers. This special property enables the encapsulation of various molecules, such as protein and enzymes, but only at low pH. It is possible to stabilize the capsid at pH 7.5 by addition of negatively charged polyelectrolytes or negatively charged particles, but these methods all fill the interior of the capsid, leaving little or no space for other cargo molecules. This pH restriction therefore severely limits the range of enzymes that can be encapsulated, and hampers the investigation of the CCMV capsid as a nanoreactor for the study of enzymes in confined spaces. Herein, the interaction of N-terminal histidine-tag-modified capsid proteins with several metal ions is reported. Depending on the conditions used, nanometer-sized protein particles or capsidlike architectures are formed that are stable at pH 7.5. This metal-mediated stabilization methodology is employed to form stable capsids containing multiple proteins at pH 7.5, thereby greatly expanding the scope of the CCMV capsid as a nanoreactor. The cowpea chlorotic mottle virus capsid, devoid of RNA, is stable at pH 5.0 but disassembles into dimers at pH 7.5. Capsid proteins modified with an N-terminal histidine tag can be stabilized at pH 7.5 by the addition of nickel ions to the assembled capsids at pH 5.0, followed by dialysis to pH 7.5.
KW - CCMV
KW - nickel
KW - protein engineering
KW - self-assembly
KW - supramolecular chemistry
UR - http://www.scopus.com/inward/record.url?scp=79953761120&partnerID=8YFLogxK
U2 - 10.1002/smll.201001777
DO - 10.1002/smll.201001777
M3 - Article
C2 - 21381194
AN - SCOPUS:79953761120
SN - 1613-6810
VL - 7
SP - 911
EP - 919
JO - Small : Nano Micro
JF - Small : Nano Micro
IS - 7
ER -