Lipocalin Blc is a potential heme ‐binding protein

AbstractLipocalins are a superfamily of functionally diverse proteins defined by a well ‐conserved tertiary structure despite variation in sequence. Lipocalins bind and transport small hydrophobic molecules in organisms of all kingdoms. However, there is still uncertainty regarding the function of some members of the family, including bacterial lipocalin Blc fromEscherichia coli. Here, we present evidence that lipocalin Blc may be involved in heme binding, trans ‐periplasmic transport, or heme storage. This conclusion is supported by a co‐crystal structure, mass spectrometric data, absorption titration, andin silico analysis. Binding of heme is observed at low micromolar range with one ‐to‐one ligand‐to‐protein stoichiometry. However, the absence of classical coordination to the iron atom leaves the possibility that the primary ligand of Blc is another tetrapyrrole.

Source: FEBS Letters - November 19, 2020 Category: Biochemistry Authors: Nina G. Bozhanova, M. Wade Calcutt, William N. Beavers, Benjamin P. Brown, Eric P. Skaar, Jens Meiler Tags: RESEARCH ARTICLE Source Type: research