title: Packing and loop-structure variations in non-isomorphous crystals of FabZ from Plasmodium falciparum.
abstract: The crystals obtained from various batches of crystallization trials of FabZ from Plasmodium falciparum exhibited non-isomorphism. The c axis of the I222 cell showed a large variation of about 16 A, from c = 81 A to c = 97 A. Complete data sets were collected for three crystal forms with varying lengths of the c axis (form 1, c = 97 A; form 2, c = 92 A; form 3, c = 81 A). The crystal structure of form 1 has been reported previously. Here, the crystal structures of the other two crystal forms are reported and a detailed structural comparison is made of the three crystal forms in order to explore the possible reasons for the existence of non-isomorphism. The conformations of three loops vary between the three crystal forms. The disposition of the loops affects the crystal packing and hence the unit-cell parameter. The crystallization condition and crystallization method employed, which change the evaporation rate, determine the crystal form of the enzyme. The present analysis shows that pH-induced intrinsic conformational changes in the protein play a key role in the observed differences.
authors: Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India.
authors: Pidugu Lakshmi
authors: PL
authors: Swarnamukhi
authors: Shailendra Kumar
authors: SK
authors: Sharma
authors: Prasanth
authors: P
authors: Padala
authors: Namita
authors: N
authors: Surolia
authors: Avadhesha
authors: A
authors: Surolia
authors: Kaza
authors: K
authors: Suguna
mesh_terms: D000818:Animals; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D008958:Models, Molecular; D010963:Plasmodium falciparum / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D015800:Protozoan Proteins