The crystal and molecular structure of N-acetylactinobolin: the α-helix in a small peptide

Powder crystallography on macromolecules

“…The possibility of using powder diffraction data on microcrystalline protein samples for detection of ligands in proteinligand complexes was illustrated by the studies of HEWL complexes with N-acetylglucosamine (NAGn, n = 1-6) oligo- saccharides (Von Dreele, 2001, 2005. All of the protein powder diffraction patterns in these studies showed extremely sharp Bragg peaks consistent with crystallites greater than 1 mm in size, which were also devoid of line-broadening defects.…”

Protein powder diffraction – pH variation studies of insulin

“…Especially, when the lattice distortion is anisotropic, which is often the case in organic compounds, it is hard to identify the correct phase. [1] We have developed a new search/match algorithm which detects and evaluates the anisotropic lattice distortion and intensity deformation due to the preferred orientations. In Figure 1, overlay of the observed powder pattern downloaded from the Search-Match Round Robin-2002 web site [1] and the pattern registered in the ICDD database [2] is shown.…”

“…[1] We have developed a new search/match algorithm which detects and evaluates the anisotropic lattice distortion and intensity deformation due to the preferred orientations. In Figure 1, overlay of the observed powder pattern downloaded from the Search-Match Round Robin-2002 web site [1] and the pattern registered in the ICDD database [2] is shown. The inconsistency between these patterns is due to the lattice distortion of the observed pattern with its lattice constants (a, c)=(9.09, 13.47) from the ICDD pattern (a, c)=(9.19, 13.40).…”

“…The second method has developed for simultaneous QPA of group of powder patterns with identical qualitative phase composition of samples. The method is development of J.Rius [1] and K.Zangalis [2] methods but differ by iterative refinement mass absorption coefficients of samples and calibrate constants or corundum numbers of phases which made by least squares or simplex methods.…”

Protein powder diffraction at cryocooled conditions

“…Because of its dietary and pharmaceutical usefulness, various characteristics of aspartame, including the model of its receptor site and its conformation in aqueous solution, have been studied extensively [1,2]. Aspartame is known to grow in different pseudo-polymorphic forms, IA, IB, IIA and IIB, each containing a different amount of water and all having a needle-like morphology.…”