2PFE: Crystal Structure Of Thermobifida Fusca Protease A (Tfpa)

Obtaining detailed knowledge of folding intermediate and transition state (TS) structures is critical for understanding protein folding mechanisms. Comparisons between proteins adapted to survive extreme temperatures with their mesophilic homologs are likely to provide valuable information on the interactions relevant to the unfolding transition. For kinetically stable proteins such as alpha-lytic protease (alphaLP) and its family members, their large free energy barrier to unfolding is central to their biological function. To gain new insights into the mechanisms that underlie kinetic stability, we have determined the structure and high temperature unfolding kinetics of a thermophilic homolog, Thermobifida fusca protease A (TFPA). These studies led to the identification of a specific structural element bridging the N and C-terminal domains of the protease (the "domain bridge") proposed to be associated with the enhanced high temperature kinetic stability in TFPA. Mutagenesis experiments exchanging the TFPA domain bridge into alphaLP validate this hypothesis and illustrate key structural details that contribute to TFPA's increased kinetic thermostability. These results lead to an updated model for the unfolding transition state structure for this important class of proteases in which domain bridge undocking and unfolding occurs at or before the TS. The domain bridge appears to be a structural element that can modulate the degree of kinetic stability of the different members of this class of proteases.
PDB ID: 2PFEDownload
MMDB ID: 47222
PDB Deposition Date: 2007/4/4
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.44  Å
Source Organism:
Similar Structures:
Biological Unit for 2PFE: monomeric; determined by author and by software (PISA)
Molecular Components in 2PFE
Label Count Molecule
Protein (1 molecule)
Alkaline Serine Protease
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB