Showing papers by "Jonathan B. Wittenberg published in 1991"
TL;DR: Kraus et al. as discussed by the authors showed that the most likely candidate for the distal residue at position E7, based on the alignment with other globins, is Gln 65.
Abstract: The cytoplasmic hemoglobin II from the gill of the clamLucina pectinata consists of 150 amino acid residues, has a calculatedMm of 17,476, including heme and an acetylated N-terminal residue. It retains the invariant residues Phe 44 at position CD1 and His 65 at the proximal position F8, as well as the highly conserved Trp 15 at position A12 and Pro 38 at position C2. The most likely candidate for the distal residue at position E7, based on the alignment with other globins, is Gln 65. However, optical and EPR spectroscopic studies of the ferri Hb II (Kraus, D. W., Wittenberg, J. B., Lu, J. F., and Peisach, J.,J. Biol. Chem.265, 16054–16059, 1990) have implicated a tyrosinate oxygen as the distal ligand. Modeling of theLucina Hb II sequence, using the crystal structure of sperm whale aquometmyoglobin, showed that Tyr 30 substituting for the Leu located at position B10 can place its oxygen within 2.8 A of the water molecule occupying the distal ligand position. This structural alteration is facilitated by the coordinate mutation of the residue at position CD4, from Phe 46 in the sperm whale myoglobin sequence to Leu 47 inLucina Hb II.
24 citations
01 Jan 1991
TL;DR: This essay attempts to define the role of Hb in each symbiosis between plants and intracellular prokaryotes and between molluscs and intrACEllular proKaryotes.
Abstract: Cytoplasmic Hb, developed by the host, is a constant feature o f symbioses between plants and intracellular prokaryotes and between molluscs and intracellular prokaryotes. This essay attempts to define the role of Hb in each symbiosis.
12 citations
TL;DR: Diffraction data to 31 A resolution were collected on crystals of a complex of components II and III of the cytoplasmic hemoglobin of the symbiont-harboring clam Lucina pectinata as mentioned in this paper.
8 citations
TL;DR: By careful control of the buffering medium composition, it has been possible to obtain stable crystals of the deoxy, oxy and sulfide forms of the protein and to show that the crystals contain the ferric form of L. pectinata "sulfide reactive" hemoglobin I.
2 citations
01 Jan 1991
TL;DR: The Puerto Rican clam Lucina pectinata, a bivalve mollusc, has three cytoplasmic Hbs associated with its gill: HbI, HbII and HbIII, which assist in symbiosis with intracellular chemoautotrophic bacteria.
Abstract: The Puerto Rican clam Lucina pectinata, a bivalve mollusc, has three cytoplasmic Hbs associated with its gill: HbI, HbII and HbIII. The clam utilizes these three Hbs in symbiosis with intracellular chemoautotrophic bacteria (1). These bacteria reside in the gill of the clam where its requirement for O2 and hydrogen sulfide is provided by the clam via the Hbs (2)