The HI0073/HI0074 Protein Pair From Haemophilus Influenzae is a Member of a New Nucleotidyltransferase Family: Structure, Sequence Analyses, and Solution Studies

Published

February 1, 2003

Author(s)

C Lehmann, Kap Lim, V R. Chalamasetty, W Krajewski, E Melamud, Andrey Galkin, A Howard, Z Kelman, Prasad T. Reddy, A Murzin, O Herzberg

Abstract

The crystal structure of HI0074 from Haemophilus influenzae, a protein of unknown function, has been determined at a resolution of 2.4 . The molecules form an up-down four-helix bundle, and associate into homodimers. The fold is most closely related to the substrate-binding domain of KNT, yet the amino acid sequences of the two proteins exhibit no significant homology. Sequence analyses of completely and incompletely sequenced genomes reveals that the two adjacent genes, HI0074 and HI0073, and their close relatives, comprise a new family of nucleotidyltransferases with 15 members at the time of writing. The analyses also indicates that this is one of 8 families of a large nucleotidyltransferase superfamily, whose members were identified based on the proximity of the nucleotide- and substrate-binding domains on the respective genomes. Both HI0073 and HI0074 were annotated 'hypothetical' in the original genome sequencing publication. HI0073 was cloned, expressed and purified, and was shown to form a complex with HI0074 by polyacrylamide gel electrophoresis under non-denaturing conditions, analytical size exclusion chromatography, and by dynamic light scattering. Double stranded and single stranded DNA binding assays showed no evidence of DNA binding to HI0074 or to HI0073/HI0074 complex despite the suggestive shape of the putative binding cleft formed by the HI0074 dimer.

Citation

Proteins-Structure Function And Genetics

Volume

50

Issue

No. 2

Pub Type

Journals

Keywords

haemophilus influenzae, hypothetical proteins 0073/0074, nucleotidytransferases

Citation

Lehmann, C. , Lim, K. , Chalamasetty, V. , Krajewski, W. , Melamud, E. , Galkin, A. , Howard, A. , Kelman, Z. , Reddy, P. , Murzin, A. and Herzberg, O. (2003), The HI0073/HI0074 Protein Pair From Haemophilus Influenzae is a Member of a New Nucleotidyltransferase Family: Structure, Sequence Analyses, and Solution Studies, Proteins-Structure Function And Genetics (Accessed September 9, 2024)