title: High-phasing-power lanthanide derivatives: taking advantage of ytterbium and lutetium for optimized anomalous diffraction experiments using synchrotron radiation.
abstract: Ytterbium and lutetium are well suited for optimized anomalous diffraction experiments using synchrotron radiation. Therefore, two lanthanide complexes Yb-HPDO3A and Lu-HPDO3A have been produced that are similar to the Gd-HPDO3A complex already known to give good derivative crystals. Derivative crystals of hen egg-white lysozyme were obtained by co-crystallization using 100 mM solutions of each lanthanide complex. De novo phasing has been carried out using single-wavelength anomalous diffraction on data sets collected on each derivative crystal at the L(III) absorption edge of the corresponding lanthanide (ff" = 28 e(-)). A third data set was collected on a Lu-HPDO3A derivative crystal at the Se K absorption edge with f"(Lu) = 10 e(-). The structures were refined and compared with the known structure of the Gd-HPDO3A lysozyme derivative. The quality of the experimental electron-density maps allows easy model building. With L(III) absorption edges at shorter wavelengths than the gadolinium absorption edge, lutetium and ytterbium, when chelated by a ligand such as HPDO3A, form lanthanide complexes that are especially interesting for synchrotron-radiation experiments in structural biology.
mesh_terms: D000818:Animals; D002645:Chickens; D003460:Crystallization / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods* / Q000706:statistics & numerical data; D005682:Gadolinium / Q000737:chemistry; D008187:Lutetium / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D017356:Synchrotrons; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D009942:Organometallic Compounds; D008187:Lutetium; D005682:Gadolinium; C421864:hen egg lysozyme; D009113:Muramidase; D015018:Ytterbium