Structural and biochemical characterisation of Co 2+ -binding sites on serum albumins and their interplay with fatty acids.

Autor:	Wu D; School of Medicine, University of St Andrews St Andrews UK ajs21@st-andrews.ac.uk +44 (0)1334 463546., Gucwa M; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville VA 22908-0736 USA wladek@iwonka.med.virginia.edu +1 434-243-6865.; Doctoral School of Exact and Natural Sciences, Jagiellonian University Krakow Poland., Czub MP; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville VA 22908-0736 USA wladek@iwonka.med.virginia.edu +1 434-243-6865., Cooper DR; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville VA 22908-0736 USA wladek@iwonka.med.virginia.edu +1 434-243-6865., Shabalin IG; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville VA 22908-0736 USA wladek@iwonka.med.virginia.edu +1 434-243-6865., Fritzen R; School of Medicine, University of St Andrews St Andrews UK ajs21@st-andrews.ac.uk +44 (0)1334 463546., Arya S; School of Medicine, University of St Andrews St Andrews UK ajs21@st-andrews.ac.uk +44 (0)1334 463546., Schwarz-Linek U; Biomedical Sciences Research Complex, University of St Andrews St Andrews UK., Blindauer CA; Department of Chemistry, University of Warwick Coventry UK., Minor W; Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine Charlottesville VA 22908-0736 USA wladek@iwonka.med.virginia.edu +1 434-243-6865., Stewart AJ; School of Medicine, University of St Andrews St Andrews UK ajs21@st-andrews.ac.uk +44 (0)1334 463546.
Jazyk:	angličtina
Zdroj:	Chemical science [Chem Sci] 2023 May 23; Vol. 14 (23), pp. 6244-6258. Date of Electronic Publication: 2023 May 23 (Print Publication: 2023).
DOI:	10.1039/d3sc01723k
Abstrakt:	Serum albumin-Co 2+ interactions are of clinical importance. They play a role in mediating the physiological effects associated with cobalt toxicity and are central to the albumin cobalt binding (ACB) assay for diagnosis of myocardial ischemia. To further understand these processes, a deeper understanding of albumin-Co 2+ interactions is required. Here, we present the first crystallographic structures of human serum albumin (HSA; three structures) and equine serum albumin (ESA; one structure) in complex with Co 2+ . Amongst a total of sixteen sites bearing a cobalt ion across the structures, two locations were prominent, and they relate to metal-binding sites A and B. Site-directed mutagenesis and isothermal titration calorimetry (ITC) were employed to characterise sites on HSA. The results indicate that His9 and His67 contribute to the primary (putatively corresponding to site B) and secondary Co 2+ -binding sites (site A), respectively. The presence of additional multiple weak-affinity Co 2+ binding sites on HSA was also supported by ITC studies. Furthermore, addition of 5 molar equivalents of the non-esterified fatty acid palmitate (C16:0) reduced the Co 2+ -binding affinity at both sites A and B. The presence of bound myristate (C14:0) in the HSA crystal structures provided insight into the fatty acid-mediated structural changes that diminish the affinity of the protein toward Co 2+ . Together, these data provide further support for the idea that ischemia-modified albumin corresponds to albumin with excessive fatty-acid loading. Collectively, our findings provide a comprehensive understanding of the molecular underpinnings governing Co 2+ binding to serum albumin. Competing Interests: One of the authors (W. M.) notes that he has also been involved in the development of state-of-the-art software, data management and mining tools; some of these have been commercialized by HKL Research and are mentioned in the paper. W. M. is the co-founder of HKL Research and a member of the board. The authors have no other relevant affiliations or financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. (This journal is © The Royal Society of Chemistry.)
Databáze:	MEDLINE
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