Different forms of African cassava mosaic virus capsid protein within plants and virions

Katharina Hipp; Kerstin Zikeli; Gabi Kepp; Lena Schmid; Robert L Shoeman; Tomasz P Jurkowski; Tatjana Kleinow; Holger Jeske

doi:10.1016/j.virol.2019.01.018

Different forms of African cassava mosaic virus capsid protein within plants and virions

Virology. 2019 Mar:529:81-90. doi: 10.1016/j.virol.2019.01.018. Epub 2019 Jan 17.

Authors

Katharina Hipp¹, Kerstin Zikeli², Gabi Kepp², Lena Schmid², Robert L Shoeman³, Tomasz P Jurkowski⁴, Tatjana Kleinow², Holger Jeske²

Affiliations

¹ University of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany. Electronic address: katharina.hipp@tuebingen.mpg.de.
² University of Stuttgart, Institute of Biomaterials and Biomolecular Systems, Department of Molecular Biology and Plant Virology, Pfaffenwaldring 57, 70550 Stuttgart, Germany.
³ Max Planck Institute for Medical Research, Department of Biomolecular Mechanisms, Analytical Protein Biochemistry, Jahnstr. 29, 69120 Heidelberg, Germany.
⁴ University of Stuttgart, Institute of Biochemistry and Technical Biochemistry, Department of Biochemistry, Allmandring 31, 70550 Stuttgart, Germany.

PMID: 30684693
DOI: 10.1016/j.virol.2019.01.018

Abstract

One geminiviral gene encodes the capsid protein (CP), which can appear as several bands after electrophoresis depending on virus and plant. African cassava mosaic virus-Nigeria CP in Nicotiana benthamiana, however, yielded one band (~ 30 kDa) in total protein extracts and purified virions, although its expression in yeast yielded two bands (~ 30, 32 kDa). Mass spectrometry of the complete protein and its tryptic fragments from virions is consistent with a cleaved start M1, acetylated S2, and partial phosphorylation at T12, S25 and S62. Mutants for additional potentially modified sites (N223A; C235A) were fully infectious and formed geminiparticles. Separation in triton acetic acid urea gels confirmed charge changes of the CP between plants and yeast indicating differential phosphorylation. If the CP gene alone was expressed in plants, multiple bands were observed like in yeast. A high turnover rate indicates that post-translational modifications promote CP decay probably via the ubiquitin-triggered proteasomal pathway.

Keywords: CP; Capsid protein; Geminivirus; Mass spectrometry; Ubiquitination; Virus particles.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Amino Acid Sequence
Begomovirus / physiology*
Capsid Proteins / genetics*
Capsid Proteins / metabolism*
DNA, Viral
Models, Molecular
Phosphorylation
Plant Diseases / virology
Protein Conformation
Protein Isoforms
Virus Replication*

Substances

Capsid Proteins
DNA, Viral
Protein Isoforms

Supplementary concepts

African cassava mosaic virus