ProfessorCanada Research Chair in Blood Proteins
Iron is essential for life, and the average adult human body contains 3.5 grams of iron. Both excess iron and iron deficiency are pathological, so regulation of iron uptake and distribution to tissues in which it will be used requires a sophisticated metabolic system to monitor iron status and distribution and to assure iron homeostasis. This situation is complicated further by the insolubility of non-chelated Fe 3+ at physiological pH and competition for iron with infectious bacteria and parasites.
Hemopexin, transferrin, Dcytb, and bacterioferritin are the principal proteins involved in iron metabolism that we are studying. Hemopexin is the heme scavenging glycoprotein from human plasma that removes heme released to the circulation by hemolysis or rhabdomyolysis and thereby provides protection against oxidative damage to tissue catalyzed by unbound heme. Transferrin is the plasma protein that is primarily responsible for transport and distribution of iron from the gut and liver to tissues requiring iron. Dcytb is an integral membrane protein of the duodenal mucosa that has been proposed to be responsible for reduction of dietary iron from Fe 3+ to Fe 2+ and thereby promote iron uptake by the divalent metal transporter, Dmt1. Bacterioferritin is a bacterial form of ferritin that differs in part in that it is comprised of a single type of subunit and is able to bind heme. For these proteins, our general approach is to apply a variety of spectroscopic, kinetic, thermodynamic and structural strategies to characterize the manner in which the protein environment influences the chemical and physical properties of the iron center. Our studies concerning recombinant forms of transferrin are performed in collaboration with the group of Professor Ross MacGillivray (UBC), and our studies of bacterioferritin are performed in collaboration with the groups of Professor Geoffrey Moore and Dr. Nick Le Brun (University of East Anglia , U.K. ).
Postdoctoral, California Institute of Technology, 1976-79
M.D. Medical College of Wisconsin, 1976
Ph.D. (Biochemistry), Med. College of Wisconsin, 1976
B.Sc. (Chemistry), Lawrence University, 1969
- Hunter CL, Mauk AG. Engineered metalloregulation of azide binding affinity and reduction potential of horse heart myoglobin. Dalton Trans. 2012 Dec 19.
- Alam S, Yee J, Couture M, Takayama SJ, Tseng WH, Mauk AG, Rafferty S. Cytochrome b(5) from Giardia lamblia. Metallomics. 2012 Dec 21;4(12):1255-61.
- Kuo HH, Mauk AG. Indole peroxygenase activity of indoleamine 2,3-dioxygenase. Proc Natl Acad Sci U S A. 2012 Aug 28;109(35):13966-71.
- Ukpabi G, Takayama SJ, Mauk AG, Murphy ME. Inactivation of the heme degrading enzyme IsdI by an active site substitution that diminishes heme ruffling. J Biol Chem. 2012 Oct 5;287(41):34179-88.
- Williams DE, Steinø A, de Voogd NJ, Mauk AG, Andersen RJ. Halicloic acids A and B isolated from the marine sponge Haliclona sp. collected in the Philippines inhibit indoleamine 2,3-dioxygenase. J Nat Prod. 2012 Aug 24;75(8):1451-8.
- Wong SG, Abdulqadir R, Le Brun NE, Moore GR, Mauk AG. Fe-haem bound to Escherichia coli bacterioferritin accelerates iron core formation by an electron transfer mechanism. Biochem J. 2012 Jun 15;444(3):553-60.
- Kumar R, Mauk AG. Protonation and anion binding control the kinetics of iron release from human transferrin. J Phys Chem B. 2012 Mar 29;116(12):3795-807.
- Zheng P, Takayama SI, Mauk AG, Li H. Hydrogen Bond Strength Modulates the Mechanical Strength of Ferric-thiolate Bonds in Rubredoxin. J Am Chem Soc. 2012 Feb 6. [Epub ahead of print]
- Lelj-Garolla B, Mauk AG. Roles of the N- and C-terminal sequences in Hsp27 self-association and chaperone activity. Protein Sci. 2012 Jan;21(1):122-33.
- Takayama SJ, Ukpabi G, Murphy ME, Mauk AG. Electronic properties of the highly ruffled heme bound to the heme degrading enzyme IsdI. Proc Natl Acad Sci U S A. 2011 Aug 9;108(32):13071-6.
- Rosell FI, Kuo HH, Mauk AG. NADH oxidase activity of indoleamine 2,3-dioxygenase. J Biol Chem. 2011 Aug 19;286(33):29273-83.
- Mauk MR, Mauk AG. Metal ions and electrolytes regulate the dissociation of heme from human hemopexin at physiological pH. J Biol Chem. 2010 Jul 2;285(27):20499-506.
- Le Brun NE, Crow A, Murphy ME, Mauk AG, Moore GR. Iron core mineralisation in prokaryotic ferritins. Biochim Biophys Acta. 2010 Aug;1800(8):732-44.
- MacPherson IS, Rosell FI, Scofield M, Mauk AG, Murphy ME. Directed evolution of copper nitrite reductase to a chromogenic reductant. Protein Eng Des Sel. 2010 Mar;23(3):137-45.
- Mauk MR, Rosell FI, Mauk AG Metal ion facilitated dissociation of heme from b-type heme proteins.. J Am Chem Soc. 2009 Nov 25;131(46):16976-83.
- Kumar R, Mauk AG.Atypical effects of salts on the stability and iron release kinetics of human transferrin. J Phys Chem B. 2009 Sep 10;113(36):12400-9.
- Carr G, Tay W, Bottriell H, Andersen SK, Mauk AG, Andersen RJ. Plectosphaeroic acids A, B, and C, indoleamine 2,3-dioxygenase inhibitors produced in culture by a marine isolate of the fungus Plectosphaerella cucumerina. Org Lett. 2009 Jul 16;11(14):2996-9.
- Lin S, Jaschke PR, Wang H, Paddock M, Tufts A, Allen JP, Rosell FI, Mauk AG, Woodbury NW, Beatty JT. Electron transfer in the Rhodobacter sphaeroides reaction center assembled with zinc bacteriochlorophyll. Proc Natl Acad Sci U S A. 2009 May 26;106(21):8537-42.
- Wong SG, Tom-Yew SA, Lewin A, Le Brun NE, Moore GR, Murphy ME, Mauk AG.Structural and mechanistic studies of a stabilized subunit dimer variant of Escherichia coli bacterioferritin identify residues required for core formation. J Biol Chem. 2009 Jul 10;284(28):18873-81.