Characterization of amino acid residues essential for tetramer formation and DNA-binding activity of ssDNA-binding protein of Mycobacterium tuberculosis

2011 ◽  
Vol 76 (6) ◽  
pp. 658-665 ◽  
Author(s):  
Hua Zhang ◽  
Yuxi Tian ◽  
Ziduo Liu ◽  
Feng Huang ◽  
Lihua Hu ◽  
...  
2011 ◽  
Vol 437 (1) ◽  
pp. 141-148 ◽  
Author(s):  
Isao Suetake ◽  
Yuichi Mishima ◽  
Hironobu Kimura ◽  
Young-Ho Lee ◽  
Yuji Goto ◽  
...  

The Dnmt3a gene, which encodes de novo-type DNA methyltransferase, encodes two isoforms, full-length Dnmt3a and Dnmt3a2, which lacks the N-terminal 219 amino acid residues. We found that Dnmt3a showed higher DNA-binding and DNA-methylation activities than Dnmt3a2. The N-terminal sequence from residues 1 to 211 was able to bind to DNA, but could not distinguish methylated and unmethylated CpG. Its binding to DNA was inhibited by a major groove binder. Four basic amino acid residues, Lys51, Lys53, Arg177 and Arg179, in the N-terminal region were crucial for the DNA-binding activity. The ectopically expressed N-terminal sequence (residues 1–211) was localized in nuclei, whereas that harbouring mutations at the four basic amino acid residues was also detected in the cytoplasm. The DNA-methylation activity of Dnmt3a with the mutations was suppressed under physiological salt conditions, which is similar that of Dnmt3a2. In addition, ectopically expressed Dnmt3a with mutations, as well as Dnmt3a2, could not be retained efficiently in nuclei on salt extraction. We conclude that the DNA-binding activity of the N-terminal domain contributes to the DNA-methyltransferase activity via anchoring of the whole molecule to DNA under physiological salt conditions.


2001 ◽  
Vol 183 (13) ◽  
pp. 4094-4098 ◽  
Author(s):  
Ke Xu ◽  
Mark A. Strauch

ABSTRACT Two truncated variants of AbrB, comprising either its first 53 (AbrBN53) or first 55 (AbrBN55) amino acid residues, were constructed and purified. Noncovalently linked homodimers of the truncated variants exhibited very weak DNA-binding activity. Cross-linking AbrBN55 dimers into tetramers and higher-order multimers (via disulfide bonding between penultimate cysteine residues) resulted in proteins having DNA-binding affinity comparable to and DNA-binding specificity identical to those of intact, wild-type AbrB. These results indicate that the DNA recognition and specificity determinants of AbrB binding lie solely within its N-terminal amino acid sequence.


Biochemistry ◽  
2010 ◽  
Vol 49 (4) ◽  
pp. 679-686 ◽  
Author(s):  
Jennifer Grants ◽  
Erin Flanagan ◽  
Andrea Yee ◽  
Paul J. Romaniuk

Bacteriophage ◽  
2012 ◽  
Vol 2 (2) ◽  
pp. 79-88 ◽  
Author(s):  
Amitava Bandhu ◽  
Tridib Ganguly ◽  
Biswanath Jana ◽  
Amritangshu Chakravarty ◽  
Anindya Biswas ◽  
...  

1994 ◽  
Vol 14 (3) ◽  
pp. 1852-1860
Author(s):  
K Nakagomi ◽  
Y Kohwi ◽  
L A Dickinson ◽  
T Kohwi-Shigematsu

The nuclear matrix attachment DNA (MAR) binding protein SATB1 is a sequence context-specific binding protein that binds in the minor groove, making virtually no contact with the DNA bases. The SATB1 binding sites consist of a special AT-rich sequence context in which one strand is well-mixed A's, T's, and C's, excluding G's (ATC sequences), which is typically found in clusters within different MARs. To determine the extent of conservation of the SATB1 gene among different species, we cloned a mouse homolog of the human STAB1 cDNA from a cDNA expression library of the mouse thymus, the tissue in which this protein is predominantly expressed. This mouse cDNA encodes a 764-amino-acid protein with a 98% homology in amino acid sequence to the human SATB1 originally cloned from testis. To characterize the DNA binding domain of this novel class of protein, we used the mouse SATB1 cDNA and delineated a 150-amino-acid polypeptide as the binding domain. This region confers full DNA binding activity, recognizes the specific sequence context, and makes direct contact with DNA at the same nucleotides as the whole protein. This DNA binding domain contains a novel DNA binding motif: when no more than 21 amino acids at either the N- or C-terminal end of the binding domain are deleted, the majority of the DNA binding activity is lost. The concomitant presence of both terminal sequences is mandatory for binding. These two terminal regions consist of hydrophilic amino acids and share homologous sequences that are different from those of any known DNA binding motifs. We propose that the DNA binding region of SATB1 extends its two terminal regions toward DNA to make direct contact with DNA.


Microbiology ◽  
2008 ◽  
Vol 154 (2) ◽  
pp. 484-490 ◽  
Author(s):  
Twishasri Das Gupta ◽  
Boudhayan Bandyopadhyay ◽  
Sujoy K. Das Gupta

2018 ◽  
Vol 114 (3) ◽  
pp. 569a
Author(s):  
Julio C. Sanchez ◽  
Liyang Zhang ◽  
Amber Liu ◽  
Miles A. Pufall ◽  
Catherine A. Musselman

2019 ◽  
Vol 116 (3) ◽  
pp. 332a
Author(s):  
Julio C. Sanchez ◽  
Liyang Zhang Zhang ◽  
Miles Pufall ◽  
Catherine Musselman

1991 ◽  
Vol 11 (3) ◽  
pp. 1566-1577 ◽  
Author(s):  
S K Thukral ◽  
A Eisen ◽  
E T Young

ADR1 is a transcription factor from Saccharomyces cerevisiae that regulates ADH2 expression through a 22-bp palindromic sequence (UAS1). Size fractionation studies revealed that full-length ADR1 and a truncated ADR1 protein containing the first 229 amino acids, which has the complete DNA-binding domain, ADR1:17-229, exist as monomers in solution. However, two complexes were formed with target DNA-binding sites. UV-cross-linking studies suggested that these two complexes represent one and two molecules of ADR1 bound to DNA. Studies of ADR1 complexes formed with wild-type UAS1, asymmetrically altered UAS1, and one half of UAS1 showed that ADR1 can bind to one half of UAS1 and gives rise to a complex containing one molecule of ADR1. Dimethyl sulfate interference studies were consistent with this interpretation and in addition indicated that purine contact sites in each half of UAS1 were identical. Increasing the distance between the two halves of UAS1 had at most a minor effect of the thermodynamics of formation of the two complexes. These data are more consistent with ADR1 binding as two independent monomers, one to each half of UAS1. However, binding of two ADR1 monomers at UAS1 is apparently essential for transactivation in vivo. Further, we have identified a stretch of 18 amino acid residues amino terminal to the zinc two-finger domains of ADR1 which is essential for DNA-binding activity. Single amino acid substitutions of residues in this region resulted in severely reduced DNA-binding activity.


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