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Preliminary X‐ray Crystallographic and Structural Analyses of a Bacteriophytochrome from Stigmatella aurantiaca
Author(s) -
Woitowich Nicole Catherine,
Garrido Carlos,
Ozarowski Wesley,
Stojkovic Emina A
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.928.15
Subject(s) - phytochrome , crystallography , tetrapyrrole , chemistry , stereochemistry , biology , botany , red light , biochemistry , enzyme
Phytochromes are red‐light photoreceptors found in plants, bacteria, and fungi. Specifically, phytochromes reversibly photoconvert between spectrally distinct red‐light (Pr) and far‐red (Pfr) light absorbing states. Biliverdin (BV), a linear tetrapyrrole is the light‐sensing molecule that initiates the photoconversion in bacteriophytochromes (Bphs). Here we report on the initial structural studies of a Bph from Stigmatella aurantiaca (SaBphP). Sequence alignment of related Bphs revealed that SaBphP is the only Bph that contains a threonine (T) instead of a conserved histidine (H) in the BV‐binding pocket of the protein. This conserved H forms a hydrogen bond with the carbonyl group of the BV D‐ring in the structures of related Bphs. SaBphP crystallized bound to BV in the Pr state in 6 different conditions. In one condition, crystals yielded diffraction to a maximum resolution of 2.65 Å. Data were collected at the BioCARS 14BM‐C beam station at the Advanced Photon Source, Argonne National Laboratory. All images were indexed, integrated, and scaled by using HKL2000. SaBphP crystals are in space group P32 (a = b = 131.1 Å, c = 96.9 Å). Initial SaBphP structure has been determined using molecular replacement method implemented in Phaser by related structure of a homologous Bph from R. palustris (RpBphP3) as a search model. Supported by NIH EARDA pilot grant 5G11HD049644 – 04 to E.A.S.