Pirin is a recently identified eukaryotic protein implicated in transcriptional activation and apoptosis. Homologues of Pirin are highly conserved in both prokaryotes and eukaryotes, but their function remains poorly understood. We present here the crystal structure of the yhhW gene product, a putative Pirin homologue, from Escherichia coli and confirm its structural similarity to Pirin. The YhhW protein displays a bicupin fold with a single N-terminal metal coordination site. Molecular surface comparisons of YhhW and Pirin with structurally similar proteins suggested quercetin as a potential ligand. We demonstrate that both bacterial and human Pirins have quercetinase activity, which is inhibited by the addition of typical inhibitors of the quercetin 2,3-dioxygenase reaction. We also demonstrate the release of carbon monoxide as a reaction product. This is the first report of enzymatic activity for any member of the Pirin family and may be an important connection to their roles in transcriptional regulation.Pirin is a recently identified protein that is localized to subnuclear dotlike structures in a wide variety of human tissues (1). Pirins are highly conserved among mammals, plants, fungi, and prokaryotes and have been classified as a subfamily of the cupin superfamily on the basis of both sequence and structural similarity (1, 2). The cupin superfamily is one of the most functionally diverse protein classes and includes both enzymatic and nonenzymatic members, ranging from isomerases and epimerases that are involved in the modification of cell wall carbohydrates to nonenzymatic storage proteins in plant seeds and transcriptional cofactors in humans (2). Cupin proteins typically maintain a highly conserved GX 5 HXHX 3,4 -EX 6 G metal-binding motif, along with a GX 5 PXGX 2 HX 3 N motif, and a conserved -barrel fold. The structure of human Pirin (hPirin), 1 the only structure of a Pirin determined to date, also displays two cupin domains, consistent with other bicupin family members (3). The function of Pirin is not known, and no enzymatic activity has been described for any of the homologues. Early studies demonstrated the ability of hPirin to interact with the nuclear factor I/CCAAAT box transcription factor (NF-I) (1) and the oncoprotein B cell lymphoma 3-encoded (Bcl-3) in vivo (4), suggesting that hPirin may be involved in the modulation of NFI/CTF1 transcriptional activation or possibly in other nuclear processes, such as DNA replication or repair (1). As observed with hPirin and its homologues, proteins involved with such fundamental cellular processes are highly conserved throughout evolution. Recent studies of tumor metastasis in advanced colorectal cancer have also implicated Pirin in cellular responses to polysaccharide-K, a chemoimmunotherapeutic agent from mushrooms (5).Studies of hPirin homologues in plants have suggested a possible involvement of these proteins in programmed cell death, seed germination, and seedling development. The Lepirin gene from tomato exhibited dramatically increased mRN...
BackgroundIn the UK, the recruitment of patients into clinical research is a national health research and development policy priority. There has been limited investigation of how national level factors operate as barriers or facilitators to recruitment work, particularly from the perspective of staff undertaking patient recruitment work. The aim of this study is to identify and examine staff views of the key organisational barriers and facilitators to patient recruitment work in one clinical research group located in an NHS Academic Health Science Centre.MethodsA qualitative study utilizing in-depth, one-to-one semi-structured interviews with 11 purposively selected staff with particular responsibilities to recruit and retain patients as clinical research subjects. Thematic analysis classified interview data by recurring themes, concepts, and emergent categories for the purposes of establishing explanatory accounts.ResultsThe findings highlight four key factors that staff perceived to be most significant for the successful recruitment and retention of patients in research and identify how staff located these factors within patients, studies, the research centre, the trust, and beyond the trust. Firstly, competition for research participants at an organisational and national level was perceived to undermine recruitment success. Secondly, the tension between clinical and clinical research workloads was seen to interrupt patient recruitment into studies, despite national funding arrangements to manage excess treatment costs. Thirdly, staff perceived an imbalance between personal patient burden and benefit. Ethical committee regulation, designed to protect patients, was perceived by some staff to detract from clarification and systematisation of incentivisation strategies. Finally, the structure and relationships within clinical research teams, in particular the low tacit status of recruitment skills, was seen as influential.ConclusionsThe results of this case-study, conducted in an exemplary NHS academic research centre, highlight current systematic challenges to patient recruitment and retention in clinical studies more generally as seen from the perspective of staff at the 'sharp end’ of recruiting. Staff experience is that, beyond individual clinical research design and protocol factors, wider organisational and extra-organisational norms, structures, and processes operate as significant facilitators or hindrances in the recruitment of patients as research subjects.
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