1iop Citations

Structure and function of 6,7-dicarboxyheme-substituted myoglobin.

Biochemistry 37 5487-93 (1998)
Cited: 8 times
EuropePMC logo PMID: 9548931

Abstract

Myoglobin was reconstituted with 6,7-dicarboxy-1,2,3,4,5, 8-hexamethylheme, a compact synthetic heme with the shortest acid side chains, to pursue the structural and functional consequences after intensive disruption of the heme propionate-apoglobin linkages in the native protein. The electron-withdrawing carboxylate groups directly attached to the porphyrin ring lowered the oxygen affinity by 3-fold as compared with native myoglobin. Autoxidation of the oxy derivative to the ferric protein proceeded with 1.6 x 10(-)2 min-1 at pH 7.0 and 30 degrees C. The crystallographic structure of the cyanomet myoglobin with 1.9 A resolution shows that the heme adopts a unique orientation in the protein pocket to extend the two carboxylates toward solvent sphere. The native globin fold is conserved, and the conformations of globin side chains are almost intact except for those located nearby the heme 6,7-carboxylates. The 7-carboxylate only weakly interacts with Ser92 and His97 through two mediating water molecules. The 6-carboxylate, on the other hand, forms a novel salt bridge with Arg45 owing to conformational flexibility of the guanidinium side chain. The proton NMR shows that the small heme does not fluctuate about the iron-histidine bond even at 55 degreesC, suggesting that the salt bridge between Arg45 and heme 6-carboxylate is of critical importance to recognize and fix the heme in myoglobin.

Articles - 1iop mentioned but not cited (2)

  1. Factors correlating with significant differences between X-ray structures of myoglobin. Rashin AA, Domagalski MJ, Zimmermann MT, Minor W, Chruszcz M, Jernigan RL. Acta Crystallogr D Biol Crystallogr 70 481-491 (2014)
  2. Water stabilizes an alternate turn conformation in horse heart myoglobin. Bronstein A, Marx A. Sci Rep 13 6094 (2023)


Articles citing this publication (6)

  1. Cyanide binding to Lucina pectinata hemoglobin I and to sperm whale myoglobin: an x-ray crystallographic study. Bolognesi M, Rosano C, Losso R, Borassi A, Rizzi M, Wittenberg JB, Boffi A, Ascenzi P. Biophys J 77 1093-1099 (1999)
  2. Aggregation behavior of giant amphiphiles prepared by cofactor reconstitution. Boerakker MJ, Botterhuis NE, Bomans PH, Frederik PM, Meijer EM, Nolte RJ, Sommerdijk NA. Chemistry 12 6071-6080 (2006)
  3. Circular dichroism of hemoglobin and myoglobin. Nagai M, Nagai Y, Imai K, Neya S. Chirality 26 438-442 (2014)
  4. The impact of altered protein-heme interactions on the resonance Raman spectra of heme proteins. Studies of heme rotational disorder. Rwere F, Mak PJ, Kincaid JR. Biopolymers 89 179-186 (2008)
  5. Redox properties of engineered ruthenium myoglobin. Li CZ, Taniguchi I, Mulchandani A. Bioelectrochemistry 75 182-188 (2009)
  6. Functional analysis of the iron(II) etiocorrphycene incorporated in the myoglobin heme pocket. Neya S, Nakamura M, Imai K, Funasaki N. Chem Pharm Bull (Tokyo) 49 345-346 (2001)