Singer A

References (3)

Title : Genome sequence and functional genomic analysis of the oil-degrading bacterium Oleispira antarctica - Kube_2013_Nat.Commun_4_2156
Author(s) : Kube M , Chernikova TN , Al-Ramahi Y , Beloqui A , Lopez-Cortez N , Guazzaroni ME , Heipieper HJ , Klages S , Kotsyurbenko OR , Langer I , Nechitaylo TY , Lunsdorf H , Fernandez M , Juarez S , Ciordia S , Singer A , Kagan O , Egorova O , Petit PA , Stogios P , Kim Y , Tchigvintsev A , Flick R , Denaro R , Genovese M , Albar JP , Reva ON , Martinez-Gomariz M , Tran H , Ferrer M , Savchenko A , Yakunin AF , Yakimov MM , Golyshina OV , Reinhardt R , Golyshin PN
Ref : Nat Commun , 4 :2156 , 2013
Abstract : Ubiquitous bacteria from the genus Oleispira drive oil degradation in the largest environment on Earth, the cold and deep sea. Here we report the genome sequence of Oleispira antarctica and show that compared with Alcanivorax borkumensis--the paradigm of mesophilic hydrocarbonoclastic bacteria--O. antarctica has a larger genome that has witnessed massive gene-transfer events. We identify an array of alkane monooxygenases, osmoprotectants, siderophores and micronutrient-scavenging pathways. We also show that at low temperatures, the main protein-folding machine Cpn60 functions as a single heptameric barrel that uses larger proteins as substrates compared with the classical double-barrel structure observed at higher temperatures. With 11 protein crystal structures, we further report the largest set of structures from one psychrotolerant organism. The most common structural feature is an increased content of surface-exposed negatively charged residues compared to their mesophilic counterparts. Our findings are relevant in the context of microbial cold-adaptation mechanisms and the development of strategies for oil-spill mitigation in cold environments.
ESTHER : Kube_2013_Nat.Commun_4_2156
PubMedSearch : Kube_2013_Nat.Commun_4_2156
PubMedID: 23877221
Gene_locus related to this paper: olean-olei00960 , olean-r4ym14 , olean-r4yv64 , olean-r4ys13

Title : Functional and structural characterization of four glutaminases from Escherichia coli and Bacillus subtilis - Brown_2008_Biochemistry_47_5724
Author(s) : Brown G , Singer A , Proudfoot M , Skarina T , Kim Y , Chang C , Dementieva I , Kuznetsova E , Gonzalez CF , Joachimiak A , Savchenko A , Yakunin AF
Ref : Biochemistry , 47 :5724 , 2008
Abstract : Glutaminases belong to the large superfamily of serine-dependent beta-lactamases and penicillin-binding proteins, and they catalyze the hydrolytic deamidation of L-glutamine to L-glutamate. In this work, we purified and biochemically characterized four predicted glutaminases from Escherichia coli (YbaS and YneH) and Bacillus subtilis (YlaM and YbgJ). The proteins demonstrated strict specificity to L-glutamine and did not hydrolyze D-glutamine or L-asparagine. In each organism, one glutaminase showed higher affinity to glutamine ( E. coli YbaS and B. subtilis YlaM; K m 7.3 and 7.6 mM, respectively) than the second glutaminase ( E. coli YneH and B. subtilis YbgJ; K m 27.6 and 30.6 mM, respectively). The crystal structures of the E. coli YbaS and the B. subtilis YbgJ revealed the presence of a classical beta-lactamase-like fold and conservation of several key catalytic residues of beta-lactamases (Ser74, Lys77, Asn126, Lys268, and Ser269 in YbgJ). Alanine replacement mutagenesis demonstrated that most of the conserved residues located in the putative glutaminase catalytic site are essential for activity. The crystal structure of the YbgJ complex with the glutaminase inhibitor 6-diazo-5-oxo- l-norleucine revealed the presence of a covalent bond between the inhibitor and the hydroxyl oxygen of Ser74, providing evidence that Ser74 is the primary catalytic nucleophile and that the glutaminase reaction proceeds through formation of an enzyme-glutamyl intermediate. Growth experiments with the E. coli glutaminase deletion strains revealed that YneH is involved in the assimilation of l-glutamine as a sole source of carbon and nitrogen and suggested that both glutaminases (YbaS and YneH) also contribute to acid resistance in E. coli.
ESTHER : Brown_2008_Biochemistry_47_5724
PubMedSearch : Brown_2008_Biochemistry_47_5724
PubMedID: 18459799

Title : Vertebrate genome evolution and the zebrafish gene map - Postlethwait_1998_Nat.Genet_18_345
Author(s) : Postlethwait JH , Yan YL , Gates MA , Horne S , Amores A , Brownlie A , Donovan A , Egan ES , Force A , Gong Z , Goutel C , Fritz A , Kelsh R , Knapik E , Liao E , Paw B , Ransom D , Singer A , Thomson M , Abduljabbar TS , Yelick P , Beier D , Joly JS , Larhammar D , Rosa F , Westerfield M , Zon LI , Johnson SL , Talbot WS
Ref : Nat Genet , 18 :345 , 1998
Abstract : In chordate phylogeny, changes in the nervous system, jaws, and appendages transformed meek filter feeders into fearsome predators. Gene duplication is thought to promote such innovation. Vertebrate ancestors probably had single copies of genes now found in multiple copies in vertebrates and gene maps suggest that this occurred by polyploidization. It has been suggested that one genome duplication event occurred before, and one after the divergence of ray-finned and lobe-finned fishes. Holland et al., however, have argued that because various vertebrates have several HOX clusters, two rounds of duplication occurred before the origin of jawed fishes. Such gene-number data, however, do not distinguish between tandem duplications and polyploidization events, nor whether independent duplications occurred in different lineages. To investigate these matters, we mapped 144 zebrafish genes and compared the resulting map with mammalian maps. Comparison revealed large conserved chromosome segments. Because duplicated chromosome segments in zebrafish often correspond with specific chromosome segments in mammals, it is likely that two polyploidization events occurred prior to the divergence of fish and mammal lineages. This zebrafish gene map will facilitate molecular identification of mutated zebrafish genes, which can suggest functions for human genes known only by sequence.
ESTHER : Postlethwait_1998_Nat.Genet_18_345
PubMedSearch : Postlethwait_1998_Nat.Genet_18_345
PubMedID: 9537416