Virus protein assembly in microgravity.
The coat of polyomavirus is composed of three proteins that can self-assemble to form an icosahedral capsid. VP1 represents 75% of the virus capsid protein and the VP1 capsomere subunits are capable of self assembly to form a capsid-like structure. Ground-based and orbiter studies were conducted with VP1 protein cloned in an expression vector and purified to provide ample quantities for capsomere-capsid assembly. Flight studies were conducted on STS-37 on April 5-9, 1991. Assembly initiated when a VP1 protein solution was interfaced with a Ca+2 buffer solution (pH 5.0). After four days a second alignment terminated the assembly process and allowed for glutaraldehyde fixation. Flight and ground-based samples were analyzed by electron microscopy. Ground-based experiments revealed the assembly of VP1 into capsid-like structures and a heterogenous size array of capsomere subunits. Samples reacted in microgravity, however, showed capsomeres of a homogenous size, but lack of capsid-like assembly.
Chang
D
D
BioServe Space Technologies, Kansas State University, Manhattan, KS 66506, USA.
Paulsen
A
A
Johnson
T C
TC
Consigli
R A
RA
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002213:Capsid / Q000737:chemistry* / Q000187:drug effects; D004926:Escherichia coli; D051379:Mice; D008854:Microscopy, Electron; D011120:Polyomavirus / Q000737:chemistry*; D013026:Space Flight; D014760:Viral Fusion Proteins / Q000737:chemistry* / Q000187:drug effects / Q000302:isolation & purification; D019065:Virus Assembly / Q000502:physiology*; D014893:Weightlessness
D014760:Viral Fusion Proteins; D002118:Calcium