4tsh | pdb_00004tsh

A Novel Protein Fold Forms an Intramolecular Lock to Stabilize the Tertiary Structure of Streptococcus mutans Adhesin P1

spinqualitylabelsall models 4tsh, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4tsh is a 2 chain structure with sequence from Streptococcus mutans. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: CA, MG Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function C9E3B4_STRMG Publication Abstract from PubMed The cariogenic bacterium Streptococcus mutans uses adhesin P1 to adhere to tooth surfaces, extracellular matrix components, and other bacteria. A composite model of P1 based on partial crystal structures revealed an unusual complex architecture in which the protein forms an elongated hybrid alpha/polyproline type II helical stalk by folding back on itself to display a globular head at the apex and a globular C-terminal region at the base. The structure of P1's N terminus and the nature of its critical interaction with the C-terminal region remained unknown, however. We have cocrystallized a stable complex of recombinant N- and C-terminal fragments and here describe a previously unidentified topological fold in which these widely discontinuous domains are intimately associated. The structure reveals that the N terminus forms a stabilizing scaffold by wrapping behind the base of P1's elongated stalk and physically "locking" it into place. The structure is stabilized through a highly favorable DeltaGsolvation on complex formation, along with extensive hydrogen bonding. We confirm the functional relevance of this intramolecular interaction using differential scanning calorimetry and circular dichroism to show that disruption of the proper spacing of residues 989-1001 impedes folding and diminishes stability of the full-length molecule, including the stalk. Our findings clarify previously unexplained functional and antigenic properties of P1. An intramolecular lock facilitates folding and stabilizes the tertiary structure of Streptococcus mutans adhesin P1.,Heim KP, Crowley PJ, Long JR, Kailasan S, McKenna R, Brady LJ Proc Natl Acad Sci U S A. 2014 Oct 20. pii: 201413018. PMID:25331888 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Adhesin 3D structures

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