Elsevier

Virology

Volume 250, Issue 2, 25 October 1998, Pages 388-396
Virology

Regular Article
ChlorellaVirus PBCV-1 Encodes Functional Glutamine: Fructose-6-Phosphate Amidotransferase and UDP-Glucose Dehydrogenase Enzymes

https://doi.org/10.1006/viro.1998.9388Get rights and content
Under an Elsevier user license
open archive

Abstract

DNA sequence analysis of the 330-kbChlorellavirus PBCV-1 genome unexpectedly revealed several open reading frames which encode proteins that are homologous to sugar-manipulating enzymes including glutamine:fructose-6-phosphate amidotransferase (GFAT), UDP-glucose dehydrogenase (UDP-GlcDH), and hyaluronan synthase (HAS). PBCV-1 genes encoding the putative GFAT and UDP-GlcDH enzymes were expressed inEscherichia coli,and both recombinant proteins have the predicted enzyme activity in cell free extracts. These same two genes are transcribed early in PBCV-1 infection, and both genes are widespread among theChlorellaviruses. The products of the reactions catalyzed by these two enzymes are precursors in the biosynthesis of hyaluronan polysaccharide. Previous experiments established that, like the GFAT and UDP-GlcDH genes, the HAS gene is transcribed early and encodes a functional enzyme (DeAngelis, P. L., Jing. W., Graves, M. V., Burbank, D. E., and Van Etten, J. L. (1997)Science278, 1800–1803). Interestingly, the predicted amino-acid sequences of the PBCV-1 GFAT and UDP-GlcDH enzymes are more similar to bacterial GFAT and UDP-GlcDH enzymes than to their eukaryotic counterparts. In contrast, the amino-acid sequence of the PBCV-1 HAS enzyme more closely resembles eukaryotic enzymes.

Cited by (0)

F. A. MurphyC. M. FauguetD. H. L. BishopS. A. GhabrialA. W. JarvisG. P. MartelliM. A. MayoM. D. Summers

1

Present address: Department of Biological Chemistry, Weizmann Institute of Science, 76100 Rehovot, Israel.

2

To whom correspondence and reprint requests should be addressed. Fax: 402-472-2853. E-mail:[email protected].