+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

A two- alpha -helix extra domain mediates the halophilic character of a plant-type ferredoxin from halophilic archaea

, : A two- alpha -helix extra domain mediates the halophilic character of a plant-type ferredoxin from halophilic archaea. Biochemistry Washington 44(1): 29-39

The [2Fe-2S] ferredoxin (HsFdx) of the halophilic archaeon Halobacterium salinarum exhibits a high degree of sequence conservation with plant-type ferredoxins except for an insertion of 30 amino acids near its N-terminus which is extremely rich in acidic amino acids. Unfolding studies reveal that HsFdx has an unfolding temperature of approximately 85 degrees C in 4.3 M NaCl, but of only 50 degrees C in low salinity, revealing its halophilic character. The three-dimensional structure of HsFdx was determined by NMR spectroscopy, resulting in a backbone rmsd of 0.6 A for the diamagnetic regions of the protein. Whereas the overall structure of HsFdx is very similar to that of the plant-type ferredoxins, two additional alpha-helices are found in the acidic extra domain. (15)N NMR relaxation studies indicate that HsFdx is rigid, and the flexibility of residues is similar throughout the molecule. Monitoring protein denaturation by NMR did not reveal differences between the core fold and the acidic domain, suggesting a cooperative unfolding of both parts of the molecule. A mutant of the HsFdx in which the acidic domain is replaced with a short loop of the nonhalophilic Anabaena ferredoxin shows a considerably changed expression pattern. The halophilic wild-type protein is readily expressed in large amounts in H. salinarum, but not in Escherichia coli, whereas the mutant ferredoxin could only be overexpressed in E. coli. The salt concentration was also found to play a critical role for the efficiency of cluster reconstitution: the cluster of HsFdx could be reconstituted only in a solution containing molar concentrations of NaCl, while the reconstitution of the cluster in the mutant protein proceeds efficiently in low salt. These findings suggest that the acidic domain mediates the halophilic character which is reflected in its thermostability, the exclusive expression in H. salinarum, and the ability to efficiently reconstitute the iron-sulfur cluster only at high salt concentrations.


PMID: 15628843

DOI: 10.1021/bi0485169

Other references

Bushuev, S.L.; Zaitseva, O.V.; Namazova, O.S.; Vykhristyuk, O.F., 1997: Maalox in complex treatment of children with pathology of gastrointestinal tract. Pediatriya (Moscow) 0(1): 52-56

Philip, J.; Sele, V.; Trolle, D., 1961: The human chromosome count. Some studies carried out with tissue culture. Ugeskrift for Laeger 123: 925-932

Gardiner, H.M.; Barlas, A.; Matsui, H.; Diemert, A.; Taylor, M.J.O.; Preece, J.; Gordon, F.; Greenwald, S.E.; Hecher, K., 2012: Vascular programming in twins: the effects of chorionicity and fetal therapy for twin-to-twin transfusion syndrome. We assessed vascular programming in genetically identical monochorionic twin pairs with twin-to-twin transfusion syndrome (TTTS) treated differently in utero by serial amnioreduction or fetal laser arterial photocoagulation. This case-control stud...

Laurent-Vannier, A.; Pradat-Diehl, P.; Chevignard, M.; Abada, G., 2001: Unilateral spatial and motor neglect in children. Although unilateral spatial neglect is well documented in adults after a cerebral damage, the description in children is rare and no motor neglect has yet been reported. We report four children age range from three to thirteen years old, in patien...

Valencia-Serrano, Félix.; Moreno, F.; Valencia-Serrano, Mía.; Martínez-González, M.A., 2014: Bleeding after PCI, vascular access, and falsification endpoints in observational studies. Journal of the American College of Cardiology 63(23): 2586-2587

Donovan Stephen K.; Bowen Jacqueline F.; Davis Strickland Elizabeth, 1988: Upper Cretaceous echinoderms of Jamaica; new data and new thoughts. Pages 5 1988

White, W.M.; Haber, G-Pascal.; Goel, R.K.; Crouzet, S.; Stein, R.J.; Kaouk, J.H., 2009: Single-port urological surgery: single-center experience with the first 100 cases. To present perioperative outcomes in an observational cohort of patients who underwent LaparoEndoscopic Single Site (LESS) surgery at a single academic center. A prospective study was performed to evaluate patient outcomes after LESS urologic surg...

Guimaraes M.C.S.; Celeste B.J.; Ayres D.C.stilho E.; Mineo J.R.; Diniz J.M.P., 1981: Immuno enzymatic assay enzyme linked immuno sorbent assay in muco cutaneous leishmaniasis kala azar and chagas disease an epimastigote trypanosoma cruzi antigen able to distinguish between anti trypanosoma and anti leishmania antibodies. Areas where mucocutaneous leishmaniasis, kala-azar and Chagas' disease are prevalent and often overlap in Latin America. Due to a variable degree of cross-reactivity between the 3 etiological agents and antibodies synthesized during the cours...

Duboff, G.S.; Behrman, S.J.; Hawver, D., 1961: Halochromogens in human urine associated with pregnancy and ovulation. I. Application of absorption spectroscopy to the iodinecolor complex with particular reference to catecholamines. American Journal of Obstetrics and Gynecology 81: 630-642

Wishart, M.J.; Williams, J.A.; Dixon, J.E., 1997: Characterization of STYX A novel phosphatase-like protein. FASEB Journal 11(9): A1182