Database of articles cited by EMDB/PDB/SASBDB data

Keywords
Structure methods	All X-ray diffraction NMR electron microscopy small angle scattering neutron diffraction fiber diffraction powder diffraction infrared spectroscopy EPR fluorescence transfer theoretical model Hybrid
Author
Journal
IF	>30 >20 >10 >5 all

Title	Solution structures of polcalcin Phl p 7 in three ligation states: Apo-, hemi-Mg2+-bound, and fully Ca2+-bound.
Journal, issue, pages	Proteins, Vol. 81, Issue 2, Page 300-315, Year 2013
Publish date	Nov 12, 2012
Authors	Michael T Henzl / Arthur G Sirianni / Wei G Wycoff / Anmin Tan / John J Tanner /
PubMed Abstract	Polcalcins are small EF-hand proteins believed to assist in regulating pollen-tube growth. Phl p 7, from timothy grass (Phleum pratense), crystallizes as a domain-swapped dimer at low pH. This study ...Polcalcins are small EF-hand proteins believed to assist in regulating pollen-tube growth. Phl p 7, from timothy grass (Phleum pratense), crystallizes as a domain-swapped dimer at low pH. This study describes the solution structures of the recombinant protein in buffered saline at pH 6.0, containing either 5.0 mM EDTA, 5.0 mM Mg(2+), or 100 μM Ca(2+). Phl p 7 is monomeric in all three ligation states. In the apo-form, both EF-hand motifs reside in the closed conformation, with roughly antiparallel N- and C-terminal helical segments. In 5.0 mM Mg(2+), the divalent ion is bound by EF-hand 2, perturbing interhelical angles and imposing more regular helical structure. The structure of Ca(2+)-bound Phl p 7 resembles that previously reported for Bet v 4-likewise exposing apolar surface to the solvent. Occluded in the apo- and Mg(2+)-bound forms, this surface presumably provides the docking site for Phl p 7 targets. Unlike Bet v 4, EF-hand 2 in Phl p 7 includes five potential anionic ligands, due to replacement of the consensus serine residue at -x (residue 55 in Phl p 7) with aspartate. In the Phl p 7 crystal structure, D55 functions as a helix cap for helix D. In solution, however, D55 apparently serves as a ligand to the bound Ca(2+). When Mg(2+) resides in site 2, the D55 carboxylate withdraws to a distance consistent with a role as an outer-sphere ligand. (15)N relaxation data, collected at 600 MHz, indicate that backbone mobility is limited in all three ligation states.
External links	Proteins / PubMed:23011803
Methods	SAS (X-ray synchrotron) / NMR (solution)
Structure data	SASDDJ2: Calcium-bound polcalcin Phl p 7 (polcalcin Phl p 7) Method: SAXS/SANS PDB-2lvi: Solution structure of apo-Phl p 7 Method: SOLUTION NMR PDB-2lvj: solution structure of hemi-Mg-bound Phl p 7 Method: SOLUTION NMR PDB-2lvk: Solution structure of Ca-bound Phl p 7 Method: SOLUTION NMR
Chemicals	ChemComp-MG: Unknown entry ChemComp-CA: Unknown entry
Source	phleum pratense (timothy grass)
Keywords	ALLERGEN / EF-hand protein / calcium-binding protein / magnesium-binding protein