Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In Escherichia coli, flavodoxin is the physiological electron donor for the reductive activation of the enzymes pyruvate formate-lyase, anaerobic ribonucleotide reductase, and B12-dependent methionine synthase. As a basis for studies of the interactions of flavodoxin with methionine synthase, crystal structures of orthorhombic and trigonal forms of oxidized recombinant flavodoxin from E. coli have been determined. The orthorhombic form (space group P2(1)2(1)2(1), a = 126.4, b = 41.10, c = 69.15 A, with two molecules per asymmetric unit) was solved initially by molecular replacement at a resolution of 3.0 A, using coordinates from the structure of the flavodoxin from Synechococcus PCC 7942 (Anacystis nidulans). Data extending to 1.8-A resolution were collected at 140 K and the structure was refined to an Rwork of 0.196 and an Rfree of 0.250 for reflections with I > 0. The final model contains 3,224 non-hydrogen atoms per asymmetric unit, including 62 flavin mononucleotide (FMN) atoms, 354 water molecules, four calcium ions, four sodium ions, two chloride ions, and two Bis-Tris buffer molecules. The structure of the protein in the trigonal form (space group P312, a = 78.83, c = 52.07 A) was solved by molecular replacement using the coordinates from the orthorhombic structure, and was refined with all data from 10.0 to 2.6 A (R = 0.191; Rfree = 0.249). The sequence Tyr 58-Tyr 59, in a bend near the FMN, has so far been found only in the flavodoxins from E. coli and Haemophilus influenzae, and may be important in interactions of flavodoxin with its partners in activation reactions. The tyrosine residues in this bend are influenced by intermolecular contacts and adopt different orientations in the two crystal forms. Structural comparisons with flavodoxins from Synechococcus PCC 7942 and Anaebaena PCC 7120 suggest other residues that may also be critical for recognition by methionine synthase.
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PMID:A flavodoxin that is required for enzyme activation: the structure of oxidized flavodoxin from Escherichia coli at 1.8 A resolution. 941 2

Bacteriophage phiKZ is a giant virus that efficiently infects Pseudomonas aeruginosa strains pathogenic to human and, therefore, it is attractive for phage therapy. We present here the complete phiKZ genome sequence and a preliminary analysis of its genome structure. The 280,334 bp genome is a linear, circularly permutated and terminally redundant, A+T-rich double-stranded DNA molecule. The phiKZ DNA has no detectable sequence homology to other viruses and microorganisms, and it does not contain NotI, PstI, SacI, SmaI, XhoI, and XmaIII endonuclease restriction sites. The genome has 306 open reading frames (ORFs) varying in size from 50 to 2237 amino acid residues. According to the orientation of transcription, ORFs are apparently organized into clusters and most have a clockwise direction. The phiKZ genome also encodes six tRNAs specific for Met (AUG), Asn (AAC), Asp (GAC), Leu (TTA), Thr (ACA), and Pro (CCA). A putative promoter sequence containing a TATATTAC block was identified. Most potential stem-loop transcription terminators contain the tetranucleotide UUCG loops. Some genes may be assigned as phage-encoded RNA polymerase subunits. Only 59 phiKZ gene products exhibit similarity to proteins of known function from a diversity of organisms. Most of these conserved gene products, such as dihydrofolate reductase, ribonucleoside diphosphate reductase, thymidylate synthase, thymidylate kinase, and deoxycytidine triphosphate deaminase are involved in nucleotide metabolism. However, no virus-encoded DNA polymerase, DNA replication-associated proteins, or single-stranded DNA-binding protein were found based on amino acid homology, and they may therefore be strongly divergent from known homologous proteins. Fifteen phiKZ gene products show homology to proteins of pathogenic organisms, including Mycobacterium tuberculosis, Haemophilus influenzae, Listeria sp., Rickettsia prowazakeri, and Vibrio cholerae that must be considered before using this phage as a therapeutic agent. The phiKZ coat contains at least 40 polypeptides, and several proteins are cleaved during virus assembly in a way similar to phage T4. Eleven phiKZ-encoded polypeptides are related to proteins of other bacteriphages that infect a variety of hosts. Among these are four gene products that contain a putative intron-encoded endonuclease harboring the H-N-H motif common to many double-stranded DNA phages. These observations provide evidence that phages infecting diverse hosts have had access to a common genetic pool. However, limited homology on the DNA and protein levels indicates that bacteriophage phiKZ represents an evolutionary distinctive branch of the Myoviridae family.
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PMID:The genome of bacteriophage phiKZ of Pseudomonas aeruginosa. 1191 76