1HXI

AN UNEXPECTED EXTENDED CONFORMATION FOR THE THIRD TPR MOTIF OF THE PEROXIN PEX5 FROM TRYPANOSOMA BRUCEI

Summary for 1HXI

• Entry DOI: 10.2210/pdb1hxi/pdb
• Descriptor: PEROXISOME TARGETING SIGNAL 1 RECEPTOR PEX5, MAGNESIUM ION (3 entities in total)
• Functional Keywords: alpha helical, transport protein
• Biological source: Trypanosoma brucei
• Total number of polymer chains: 1
• Total formula weight: 13737.93

Authors

Kumar, A.,Roach, C.,Hirsh, I.S.,Turley, S.,deWalque, S.,Michels, P.A.M.,Hol, W.G.J. (deposition date: 2001-01-15, release date: 2001-03-21, Last modification date: 2024-10-16)

Primary citation

Kumar, A.,Roach, C.,Hirsh, I.S.,Turley, S.,deWalque, S.,Michels, P.A.,Hol, W.G.
An unexpected extended conformation for the third TPR motif of the peroxin PEX5 from Trypanosoma brucei.
J.Mol.Biol., 307:271-282, 2001

PubMed Abstract: A number of helix-rich protein motifs are involved in a variety of critical protein-protein interactions in living cells. One of these is the tetratrico peptide repeat (TPR) motif that is involved, amongst others, in cell cycle regulation, chaperone function and post-translation modifications. So far, these helix-rich TPR motifs have always been observed to be a compact unit of two helices interacting with each other in antiparallel fashion. Here, we describe the structure of the first three TPR-motifs of the peroxin PEX5 from Trypanosoma brucei, the causative agent of sleeping sickness. Peroxins are proteins involved in peroxisome, glycosome and glyoxysome biogenesis. PEX5 is the receptor of the proteins targeted to these organelles by the "peroxisomal targeting signal-1", a C-terminal tripeptide called PTS-1. The first two of the three TPR-motifs of T. brucei PEX5 appear to adopt the canonical antiparallel helix hairpin structure. In contrast, the third TPR motif of PEX5 has a dramatically different conformation in our crystals: the two helices that were supposed to form a hairpin are folded into one single 44 A long continuous helix. Such a conformation has never been observed before for a TPR motif. This raises interesting questions including the potential functional importance of a "jack-knife" conformational change in TPR motifs.

PubMed: 11243819
DOI: 10.1006/jmbi.2000.4465

Experimental method

X-RAY DIFFRACTION (1.6 Å)