scholarly journals Identification of a Second, Non-conserved Amino Acid That Contributes to the Unique Sugar Binding Properties of the Nematode Galectin LEC-1

2008 ◽  
Vol 31 (6) ◽  
pp. 1254-1257 ◽  
Author(s):  
Mayumi Tamura ◽  
Ken-ichi Kasai ◽  
Takashi Itagaki ◽  
Takamasa Nonaka ◽  
Yoichiro Arata
2004 ◽  
Vol 133 (2) ◽  
pp. 136-144 ◽  
Author(s):  
Marja Kärkkäinen ◽  
Päivi Raunio ◽  
Jaakko Rautiainen ◽  
Seppo Auriola ◽  
Kaj Hinke ◽  
...  

2021 ◽  
Vol 77 (5) ◽  
pp. 690-702
Author(s):  
Pandian Ramesh ◽  
Selvarajan Sigamani Sundaresan ◽  
Nagaraj Shobana ◽  
Thangaraj Vinuchakkaravarthy ◽  
Kandasamy Sivakumar ◽  
...  

Crystal structures of hemoglobin (Hb) from two flightless birds, ostrich (Struthio camelus) and turkey (Meleagris gallopova), were determined. The ostrich Hb structure was solved to a resolution of 2.22 Å, whereas two forms of turkey Hb were solved to resolutions of 1.66 Å (turkey monoclinic structure; TMS) and 1.39 Å (turkey orthorhombic structure; TOS). Comparison of the amino-acid sequences of ostrich and turkey Hb with those from other avian species revealed no difference in the number of charged residues, but variations were observed in the numbers of hydrophobic and polar residues. Amino-acid-composition-based computation of various physical parameters, in particular their lower inverse transition temperatures and higher average hydrophobicities, indicated that the structures of ostrich and turkey Hb are likely to be highly ordered when compared with other avian Hbs. From the crystal structure analysis, the liganded state of ostrich Hb was confirmed by the presence of an oxygen molecule between the Fe atom and the proximal histidine residue in all four heme regions. In turkey Hb (both TMS and TOS), a water molecule was bound instead of an oxygen molecule in all four heme regions, thus confirming that they assumed the aqua-met form. Analysis of tertiary- and quaternary-structural features led to the conclusion that ostrich oxy Hb and turkey aqua-met Hb adopt the R-/RH-state conformation.


2011 ◽  
Vol 34 (7) ◽  
pp. 1134-1138 ◽  
Author(s):  
Tomoharu Takeuchi ◽  
Ken-ichi Sugiura ◽  
Kazusa Nishiyama ◽  
Hideyo Takahashi ◽  
Hideaki Natsugari ◽  
...  

2005 ◽  
Vol 26 (3) ◽  
pp. 117-121 ◽  
Author(s):  
Saori TAKAHASHI ◽  
Hironobu OGASAWARA ◽  
Kazuyuki HIWATASHI ◽  
Keishi HATA ◽  
Kazuyuki HORI ◽  
...  

2007 ◽  
Vol 101 (10) ◽  
pp. 1483-1491 ◽  
Author(s):  
Konstantina Karidi ◽  
Jan Reedijk ◽  
Nick Hadjiliadis ◽  
Achilleas Garoufis

1994 ◽  
Vol 14 (4) ◽  
pp. 2755-2766 ◽  
Author(s):  
D G Overdier ◽  
A Porcella ◽  
R H Costa

Three distinct hepatocyte nuclear factor 3 (HNF-3) proteins (HNF-3 alpha, -3 beta, and -3 gamma) are known to regulate the transcription of liver-specific genes. The HNF-3 proteins bind to DNA as a monomer through a modified helix-turn-helix, known as the winged helix motif, which is also utilized by a number of developmental regulators, including the Drosophila homeotic forkhead (fkh) protein. We have previously described the isolation, from rodent tissue, of an extensive family of tissue-specific HNF-3/fkh homolog (HFH) genes sharing homology in their winged helix motifs. In this report, we have determined the preferred DNA-binding consensus sequence for the HNF-3 beta protein as well as for two divergent family members, HFH-1 and HFH-2. We show that these HNF-3/fkh proteins bind to distinct DNA sites and that the specificity of protein recognition is dependent on subtle nucleotide alterations in the site. The HNF-3, HFH-1, and HFH-2 consensus binding sequences were also used to search DNA regulatory regions to identify potential target genes. Furthermore, an analysis of the DNA-binding properties of a series of HFH-1/HNF-3 beta protein chimeras has allowed us to identify a 20-amino-acid region, located adjacent to the DNA recognition helix, which contributes to DNA-binding specificity. These sequences are not involved in base-specific contacts and include residues which diverge within the HNF-3/fkh family. Replacement of this 20-amino-acid region in HNF-3 beta with corresponding residues from HFH-1 enabled the HNF-3 beta recognition helix to bind only HFH-1-specific DNA-binding sites. We propose a model in which this 20-amino-acid flanking region influences the DNA-binding properties of the recognition helix.


2001 ◽  
Vol 183 (6) ◽  
pp. 1921-1927 ◽  
Author(s):  
Jian Qiu ◽  
John D. Helmann

ABSTRACT Transcriptional selectivity derives, in large part, from the sequence-specific DNA-binding properties of the ς subunit of RNA polymerase. There are 17 ς factors in Bacillus subtilis which, in general, recognize distinct sets of promoters. However, some ς factors have overlapping promoter selectivity. We hypothesize that the overlap between the regulons activated by the ςX and ςW factors can be explained by overlapping specificity for the −10 region: ςX recognizes −10 elements with the sequence CGAC and ςW recognizes CGTA, while both can potentially recognize CGTC. To test this model, we mutated the ςX-specific autoregulatory site (PX), containing the −10 element CGAC, to either CGTC or GCTA. Conversely, the ςW autoregulatory site (PW) was altered from CGTA to CGTC or CGAC. Transcriptional analyses, both in vitro and in vivo, indicate that changes to the −10 element are sufficient to switch a promoter from the ςX to the ςW regulon or, conversely, from the ςW to the ςX regulon, but context effects clearly play an important role in determining promoter strength. It seems likely that these subtle differences in promoter selectivity derive from amino acid differences in conserved region 2 of ς, which contacts the −10 element. However, we were unable to alter promoter selectivity by replacements of two candidate recognition residues in ςW.


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