ABSTRACT
Researchers often face dilemmas about authorship. When the researchers are graduate students, fellows, or junior faculty, the dilemmas might involve discussions about fair criteria for more senior faculty to be acknowledged as key contributors or authors on manuscripts. This "Ethics Rounds" presents a case in which a fellow faced such a dilemma. We review current journal guidelines for authorship and some ethical considerations that should help make this process more streamlined.
Subject(s)
Authorship , Biomedical Research , Intellectual Property , EthicsABSTRACT
In pathogenic Gram-negative bacteria, many virulence factors are secreted via the two-partner secretion pathway, which consists of an exoprotein called TpsA and a cognate outer membrane translocator called TpsB. The HMW1 and HMW2 adhesins are major virulence factors in nontypeable Haemophilus influenzae and are prototype two-partner secretion pathway exoproteins. A key step in the delivery of HMW1 and HMW2 to the bacterial surface involves targeting to the HMW1B and HMW2B outer membrane translocators by an N-terminal region called the secretion domain. Here we present the crystal structure at 1.92 A of the HMW1 pro-piece (HMW1-PP), a region that contains the HMW1 secretion domain and is cleaved and released during HMW1 secretion. Structural analysis of HMW1-PP revealed a right-handed beta-helix fold containing 12 complete parallel coils and one large extra-helical domain. Comparison of HMW1-PP and the Bordetella pertussis FHA secretion domain (Fha30) reveals limited amino acid homology but shared structural features, suggesting that diverse TpsA proteins have a common structural domain required for targeting to cognate TpsB proteins. Further comparison of HMW1-PP and Fha30 structures may provide insights into the keen specificity of TpsA-TpsB interactions.
Subject(s)
Adhesins, Bacterial/chemistry , Haemophilus influenzae/chemistry , Protein Structure, Tertiary/physiology , Adhesins, Bacterial/metabolism , Bacterial Outer Membrane Proteins/chemistry , Bacterial Outer Membrane Proteins/metabolism , Bordetella pertussis/chemistry , Bordetella pertussis/metabolism , Crystallography, X-Ray , Haemophilus influenzae/metabolism , Protein Folding , Protein Structure, Secondary , Structural Homology, Protein , Structure-Activity Relationship , Virulence Factors, Bordetella/chemistry , Virulence Factors, Bordetella/metabolismABSTRACT
Omp85-like proteins represent a family of proteins involved in protein translocation, and they are present in all domains of life, except archaea. In eukaryotes, Omp85-like proteins have been demonstrated to form tetrameric pore-forming complexes that interact directly with their substrate proteins. Studies performed with bacterial Omp85-like proteins have demonstrated pore-forming activity but no evidence of multimerization. In this article, we characterize the Haemophilus influenzae HMW1B protein, an Omp85-like protein that has been demonstrated to be critical for secretion of the H. influenzae HMW1 adhesin. Analysis of purified protein by biochemical and electron microscopic techniques revealed that HMW1B forms a tetramer. Examination using liposome-swelling assays demonstrated that HMW1B has pore-forming activity, with a pore size of approximately equal to 2.7 nm. Far-Western blot analysis established that HMW1B interacts with the N terminus of HMW1. These results provide evidence that a bacterial Omp85-like protein forms a tetramer and interacts directly with a substrate protein, suggesting that the architecture and physical properties of Omp85-like proteins have been conserved throughout evolution.
