Dataset Information

A membrane-bound vertebrate globin.

ABSTRACT: The family of vertebrate globins includes hemoglobin, myoglobin, and other O(2)-binding proteins of yet unclear functions. Among these, globin X is restricted to fish and amphibians. Zebrafish (Danio rerio) globin X is expressed at low levels in neurons of the central nervous system and appears to be associated with the sensory system. The protein harbors a unique N-terminal extension with putative N-myristoylation and S-palmitoylation sites, suggesting membrane-association. Intracellular localization and transport of globin X was studied in 3T3 cells employing green fluorescence protein fusion constructs. Both myristoylation and palmitoylation sites are required for correct targeting and membrane localization of globin X. To the best of our knowledge, this is the first time that a vertebrate globin has been identified as component of the cell membrane. Globin X has a hexacoordinate binding scheme and displays cooperative O(2) binding with a variable affinity (P(50)?1.3-12.5 torr), depending on buffer conditions. A respiratory function of globin X is unlikely, but analogous to some prokaryotic membrane-globins it may either protect the lipids in cell membrane from oxidation or may act as a redox-sensing or signaling protein.

SUBMITTER: Blank M

PROVIDER: S-EPMC3176823 | biostudies-literature | 2011

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

A membrane-bound vertebrate globin.

Blank Miriam M Wollberg Jessica J Gerlach Frank F Reimann Katja K Roesner Anja A Hankeln Thomas T Fago Angela A Weber Roy E RE Burmester Thorsten T

PloS one 20110920 9

The family of vertebrate globins includes hemoglobin, myoglobin, and other O(2)-binding proteins of yet unclear functions. Among these, globin X is restricted to fish and amphibians. Zebrafish (Danio rerio) globin X is expressed at low levels in neurons of the central nervous system and appears to be associated with the sensory system. The protein harbors a unique N-terminal extension with putative N-myristoylation and S-palmitoylation sites, suggesting membrane-association. Intracellular locali ...[more]

PMID: 21949889

Similar Datasets

Project description:BACKGROUND: The vertebrate globin genes encoding the ?- and ?-subunits of the tetrameric hemoglobins are clustered at two unlinked loci. The highly conserved linear order of the genes flanking the hemoglobins provides a strong anchor for inferring common ancestry of the globin clusters. In fish, the number of ?-?-linked globin genes varies considerably between different sublineages and seems to be related to prevailing physico-chemical conditions. Draft sequences of the Atlantic cod genome enabled us to determine the genomic organization of the globin repertoire in this marine species that copes with fluctuating environments of the temperate and Arctic regions. RESULTS: The Atlantic cod genome was shown to contain 14 globin genes, including nine hemoglobin genes organized in two unlinked clusters designated ?5-?1-?1-?4 and ?3-?4-?2-?3-?2. The diverged cod hemoglobin genes displayed different expression levels in adult fish, and tetrameric hemoglobins with or without a Root effect were predicted. The novel finding of maternally inherited hemoglobin mRNAs is consistent with a potential role played by fish hemoglobins in the non-specific immune response. In silico analysis of the six teleost genomes available showed that the two ?-? globin clusters are flanked by paralogs of five duplicated genes, in agreement with the proposed teleost-specific duplication of the ancestral vertebrate globin cluster. Screening the genome of extant urochordate and cephalochordate species for conserved globin-flanking genes revealed linkage of RHBDF1, MPG and ARHGAP17 to globin genes in the tunicate Ciona intestinalis, while these genes together with LCMT are closely positioned in amphioxus (Branchiostoma floridae), but seem to be unlinked to the multiple globin genes identified in this species. CONCLUSION: The plasticity of Atlantic cod to variable environmental conditions probably involves the expression of multiple globins with potentially different properties. The interspecific difference in number of fish hemoglobin genes contrasts with the highly conserved synteny of the flanking genes. The proximity of globin-flanking genes in the tunicate and amphioxus genomes resembles the RHBDF1-MPG-?-globin-ARHGAP17-LCMT linked genes in man and chicken. We hypothesize that the fusion of the three chordate linkage groups 3, 15 and 17 more than 800 MYA led to the ancestral vertebrate globin cluster during a geological period of increased atmospheric oxygen content.

Project description:Quantifying the number of charges on peptides bound to interfaces requires reliable estimates of (i) surface coverage and (ii) surface charge, both of which are notoriously difficult parameters to obtain, especially at solid/water interfaces. Here, we report the thermodynamics and electrostatics governing the interactions of l-lysine and l-arginine octamers (Lys8 and Arg8) with supported lipid bilayers prepared from a 9 : 1 mixture of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt) (DMPG) from second harmonic generation (SHG) spectroscopy, quartz crystal microbalance with dissipation monitoring (QCM-D) and nanoplasmonic sensing (NPS) mass measurements, and atomistic simulations. The combined SHG/QCM-D/NPS approach provides interfacial charge density estimates from mean field theory for the attached peptides that are smaller by a factor of approximately two (0.12 ± 0.03 C m-2 for Lys8 and 0.10 ± 0.02 C m-2 for Arg8) relative to poly-l-lysine and poly-l-arginine. These results, along with atomistic simulations, indicate that the surface charge density of the supported lipid bilayer is neutralized by the attached cationic peptides. Moreover, the number of charges associated with each attached peptide is commensurate with those found in solution; that is, Lys8 and Arg8 are fully ionized when attached to the bilayer. Computer simulations indicate Lys8 is more likely than Arg8 to "stand-up" on the surface, interacting with lipid headgroups through one or two sidechains while Arg8 is more likely to assume a "buried" conformation, interacting with the bilayer through up to six sidechains. Analysis of electrostatic potential and charge distribution from atomistic simulations suggests that the Gouy-Chapman model, which is widely used for mapping surface potential to surface charge, is semi-quantitatively valid; despite considerable orientational preference of interfacial water, the apparent dielectric constant for the interfacial solvent is about 30, due to the thermal fluctuation of the lipid-water interface.

Dataset Information

A membrane-bound vertebrate globin.

Publications

A membrane-bound vertebrate globin.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets