A photoaffinity label for the siderophore-mediated iron transport system in Neurospora crassa

• Published in: Biochimica et biophysica acta Vol. 883; no. 2; pp. 299 - 305
• Main Authors: Bailey, Christopher T., Kime-Hunt, Ellen M., Carrano, Carl J., Huschka, Hans-Georg, Winkelmann, Gunther
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04.09.1986; Elsevier; North-Holland
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; iron; Iron transport; Microbiology; Mycology; N. crassa; Neurospora crassa; Photoaffinity labeling; photosensitivity; Siderophore; Photoaffinity labeling; Siderophore; N. crassa; Iron transport; HSAB; ABCB; Fungi; Yeast; Transportation system; Ascomycetes; Iron; Neurospora crassa; Inhibition; Thallophyta
• ISSN: 0304-4165; 0006-3002; 1872-8006; 1878-2434
• DOI: 10.1016/0304-4165(86)90322-3

A photoaffinity derivative of the coprogen class of siderophores, p-azidobenzoylcoprogen B, has been synthetized. In the dark it is recognized and taken up by the iron transport system in Neurospora crassa ( arg-5, ota, aga) in a concentration-dependent manner ( K m = 6 μM, V max = 0.2 nmol·min −1·mg −1). It is also a competitive inhibitor of coprogen uptake, K I ≈ 5 μM. Photolyssis of cells with near-ultraviolet light during transport in the presence of the photoaffinity label results in approx. 50% irreversible inhibition of both coprogen and ferrichrysin uptake. Uptake of p-azidobenzoylcoprogen B itself is also inhibited upon illumination. It is proposed that this affinity label be used in isolation of the iron receptor protein(s) in N. crassa.