1TD0

Viral capsid protein SHP at pH 5.5

Summary for 1TD0

• Entry DOI: 10.2210/pdb1td0/pdb
• Descriptor: Head decoration protein (2 entities in total)
• Functional Keywords: shp, viral protein
• Biological source: Enterobacteria phage P21
• Cellular location: Virion (Potential): P36275
• Total number of polymer chains: 4
• Total formula weight: 47429.00

Authors

Chang, C.,Forrer, P.,Ott, D.,Wlodawer, A.,Plueckthun, A. (deposition date: 2004-05-21, release date: 2004-11-02, Last modification date: 2024-02-14)

Primary citation

Forrer, P.,Chang, C.,Ott, D.,Wlodawer, A.,Plueckthun, A.
Kinetic Stability and Crystal Structure of the Viral Capsid Protein SHP
J.Mol.Biol., 344:179-193, 2004

PubMed Abstract: SHP, the capsid-stabilizing protein of lambdoid phage 21, is highly resistant against denaturant-induced unfolding. We demonstrate that this high functional stability of SHP is due to a high kinetic stability with a half-life for unfolding of 25 days at zero denaturant, while the thermodynamic stability is not unusually high. Unfolding experiments demonstrated that the trimeric state (also observed in crystals and present on the phage capsid) of SHP is kinetically stable in solution, while the monomer intermediate unfolds very rapidly. We also determined the crystal structure of trimeric SHP at 1.5A resolution, which was compared to that of its functional homolog gpD. This explains how a tight network of H-bonds rigidifies crucial interpenetrating residues, leading to the observed extremely slow trimer dissociation or denaturation. Taken as a whole, our results provide molecular-level insights into natural strategies to achieve kinetic stability by taking advantage of protein oligomerization. Kinetic stability may be especially needed in phage capsids to allow survival in harsh environments.

PubMed: 15504410
DOI: 10.1016/j.jmb.2004.09.030

Experimental method

X-RAY DIFFRACTION (1.95 Å)