The crystal structure of NlpI. A prokaryotic tetratricopeptide repeat protein with a globular fold.
There are several different families of repeat proteins. In each, a distinct structural motif is repeated in tandem to generate an elongated structure. The nonglobular, extended structures that result are particularly well suited to present a large surface area and to function as interaction domains. Many repeat proteins have been demonstrated experimentally to fold and function as independent domains. In tetratricopeptide (TPR) repeats, the repeat unit is a helix-turn-helix motif. The majority of TPR motifs occur as three to over 12 tandem repeats in different proteins. The majority of TPR structures in the Protein Data Bank are of isolated domains. Here we present the high-resolution structure of NlpI, the first structure of a complete TPR-containing protein. We show that in this instance the TPR motifs do not fold and function as an independent domain, but are fully integrated into the three-dimensional structure of a globular protein. The NlpI structure is also the first TPR structure from a prokaryote. It is of particular interest because it is a membrane-associated protein, and mutations in it alter septation and virulence.
Wilson
Christopher G M
CG
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
Kajander
Tommi
T
Regan
Lynne
L
D000595:Amino Acid Sequence; D001483:Base Sequence; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D017931:DNA Primers; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics; D019077:Helix-Turn-Helix Motifs; D008074:Lipoproteins / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017510:Protein Folding; D020449:Repetitive Sequences, Amino Acid; D017386:Sequence Homology, Amino Acid
D017931:DNA Primers; D029968:Escherichia coli Proteins; D008074:Lipoproteins; C120330:NlpI protein, E coli