scholarly journals Improvement of binding activity of xylan-binding domain by amino acid substitution

2006 ◽  
Vol 50 (1) ◽  
pp. 253-254 ◽  
Author(s):  
Tomoko Sakata ◽  
Jun Takakura ◽  
Hiroyuki Miyakubo ◽  
Yuko Osada ◽  
Rieko Wada ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Binding Activity ◽  
Binding Domain

Conserved DNA binding and self-association domains of the Drosophila zeste protein

1992 ◽  
Vol 12 (2) ◽  
pp. 598-608
Author(s):  
J D Chen ◽  
C S Chan ◽  
V Pirrotta
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Amino Acid Sequence ◽  
Coiled Coil ◽  
Helical Structure ◽  
Binding Activity ◽  
Binding Domain ◽  
Drosophila Virilis ◽  
Predicted Amino Acid Sequence ◽  
Dna Binding Domain

The zeste gene product is involved in two types of genetic effects dependent on chromosome pairing: transvection and the zeste-white interaction. Comparison of the predicted amino acid sequence with that of the Drosophila virilis gene shows that several blocks of amino acid sequence have been very highly conserved. One of these regions corresponds to the DNA binding domain. Site-directed mutations in this region indicate that a sequence resembling that of the homeodomain DNA recognition helix is essential for DNA binding activity. The integrity of an amphipathic helical region is also essential for binding activity and is likely to be responsible for dimerization of the DNA binding domain. Another very strongly conserved domain of zeste is the C-terminal region, predicted to form a long helical structure with two sets of heptad repeats that constitute two long hydrophobic ridges at opposite ends and on opposite faces of the helix. We show that this domain is responsible for the extensive aggregation properties of zeste that are required for its role in transvection phenomena. A model is proposed according to which the hydrophobic ridges induce the formation of open-ended coiled-coil structures holding together many hundreds of zeste molecules and possibly anchoring these complexes to other nuclear structures.

scholarly journals Interaction with Tap42 Is Required for the Essential Function of Sit4 and Type 2A Phosphatases

2003 ◽  
Vol 14 (11) ◽  
pp. 4342-4351 ◽  
Author(s):  
Huamin Wang ◽  
Xiaodong Wang ◽  
Yu Jiang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Binding Domain ◽  
Charge Amino Acid ◽  
Catalytic Subunits ◽  
Regulatory Subunits ◽  
Terminal Domain ◽  
Major Form ◽  
Essential Function

In Saccharomyces cerevisiae, Pph21 and Pph22 are the two catalytic subunits of type 2A phosphatase (PP2Ac), and Sit4 is a major form of 2A-like phosphatase. The function of these phosphatases requires their association with different regulatory subunits. In addition to the conventional regulatory subunits, namely, the A and B subunits for Pph21/22 and the Sap proteins for Sit4, these phosphatases have been found to associate with a protein termed Tap42. In this study, we demonstrated that Sit4 and PP2Ac interact with Tap42 via an N-terminal domain that is conserved in all type 2A and 2A-like phosphatases. We found that the Sit4 phosphatase in the sit4-102 strain contains a reverse-of-charge amino acid substitution within its Tap42 binding domain and is defective for formation of the Tap42-Sit4 complex. Our results suggest that the interaction with Tap42 is required for the activity as well as for the essential function of Sit4 and PP2Ac. In addition, we showed that Tap42 is able to interact with two other 2A-like phosphatases, Pph3 and Ppg1.

scholarly journals A novel DNA-binding motif in the nuclear matrix attachment DNA-binding protein SATB1

1994 ◽  
Vol 14 (3) ◽  
pp. 1852-1860
Author(s):  
K Nakagomi ◽  
Y Kohwi ◽  
L A Dickinson ◽  
T Kohwi-Shigematsu
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Direct Contact ◽  
Binding Protein ◽  
Binding Activity ◽  
Binding Domain ◽  
Binding Motif ◽  
Dna Binding Domain ◽  
Sequence Context ◽  
Dna Binding Activity

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.

Single amino acid substitution (840Arg → His) in the hormone-binding domain of the androgen receptor leads to incomplete androgen insensitivity syndrome associated with a thermolabile androgen receptor

1994 ◽  
Vol 130 (6) ◽  
pp. 569-574 ◽  
Author(s):  
Kyosuke Imasaki ◽  
Tomonobu Hasegawa ◽  
Taijiro Okabe ◽  
Yoshiyuki Sakai ◽  
Masafumi Haji ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Androgen Insensitivity Syndrome ◽  
Binding Domain ◽  
Single Amino Acid Substitution ◽  
Single Amino Acid ◽  
Hormone Binding ◽  
Androgen Insensitivity ◽  
Hormone Binding Domain

Imasaki K, Hasegawa T. Okabe T. Sakai Y. Haji M. Takayanagi R, Nawata H. Single amino acid substitution (840Arg → His) in the hormone-binding domain of the androgen receptor leads to incomplete androgen insensitivity syndrome associated with a thermolabile androgen receptor. Eur I Endocrinol 1994;130:569–74. ISSN 0804–4643 We have characterized the androgen receptor in a Japanese girl and her maternal cousin in a family with incomplete androgen insensitivity syndrome, and have investigated the molecular basis. Wholecell androgen binding assay in cultured genital skin fibroblasts from both patients showed a normal maximum binding capacity and a normal apparent dissociation constant. However, androgen binding in fibroblasts from both patients decreased to 30% when the assay temperature was raised from 30°C to 41°C, indicating the presence of the thermolability of ligand binding to the androgen receptor. Sequence analysis of the coding exons of the androgen receptor gene from the patients revealed a single nucleotide substitution at position 2881 in exon G, resulting in the conversion of arginine (CGT) to histidine (CAT) at amino acid position 840 in the hormone-binding domain of the androgen receptor. The family study showed that the mothers and the maternal grandmother of the patients are heterozygous carriers for this mutation, whereas the father does not carry it, supporting the view that androgen insensitivity syndrome is an X chromosome-linked disorder. The single amino acid substitution may explain the qualitative abnormality of the androgen receptor displaying thermolability, which is thought to be the pathogenesis of incomplete androgen insensitivity syndrome in the patients. Kyosuke Imasaki, Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812, Japan

scholarly journals Conserved DNA binding and self-association domains of the Drosophila zeste protein.

1992 ◽  
Vol 12 (2) ◽  
pp. 598-608 ◽  
Author(s):  
J D Chen ◽  
C S Chan ◽  
V Pirrotta
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Amino Acid Sequence ◽  
Coiled Coil ◽  
Helical Structure ◽  
Binding Activity ◽  
Binding Domain ◽  
Drosophila Virilis ◽  
Predicted Amino Acid Sequence ◽  
Dna Binding Domain

The zeste gene product is involved in two types of genetic effects dependent on chromosome pairing: transvection and the zeste-white interaction. Comparison of the predicted amino acid sequence with that of the Drosophila virilis gene shows that several blocks of amino acid sequence have been very highly conserved. One of these regions corresponds to the DNA binding domain. Site-directed mutations in this region indicate that a sequence resembling that of the homeodomain DNA recognition helix is essential for DNA binding activity. The integrity of an amphipathic helical region is also essential for binding activity and is likely to be responsible for dimerization of the DNA binding domain. Another very strongly conserved domain of zeste is the C-terminal region, predicted to form a long helical structure with two sets of heptad repeats that constitute two long hydrophobic ridges at opposite ends and on opposite faces of the helix. We show that this domain is responsible for the extensive aggregation properties of zeste that are required for its role in transvection phenomena. A model is proposed according to which the hydrophobic ridges induce the formation of open-ended coiled-coil structures holding together many hundreds of zeste molecules and possibly anchoring these complexes to other nuclear structures.

scholarly journals A single amino acid change in CUP2 alters its mode of DNA binding.

1990 ◽  
Vol 10 (9) ◽  
pp. 4778-4787 ◽  
Author(s):  
C Buchman ◽  
P Skroch ◽  
W Dixon ◽  
T D Tullius ◽  
M Karin
Keyword(s):  
Amino Acid ◽  
Dna Binding ◽  
Binding Activity ◽  
Binding Domain ◽  
Single Amino Acid ◽  
Dna Binding Domain ◽  
Sequence Motifs ◽  
Wild Type ◽  
Mobility Shift ◽  
Single Amino Acid Change

CUP2 is a copper-dependent transcriptional activator of the yeast CUP1 metallothionein gene. In the presence of Cu+ and Ag+) ions its DNA-binding domain is thought to fold as a cysteine-coordinated Cu cluster which recognizes the palindromic CUP1 upstream activation sequence (UASc). Using mobility shift, methylation interference, and DNase I and hydroxyl radical footprinting assays, we examined the interaction of wild-type and variant CUP2 proteins produced in Escherichia coli with the UASc. Our results suggest that CUP2 has a complex Cu-coordinated DNA-binding domain containing different parts that function as DNA-binding elements recognizing distinct sequence motifs embedded within the UASc. A single-amino-acid substitution of cysteine 11 with a tyrosine results in decreased Cu binding, apparent inactivation of one of the DNA-binding elements and a dramatic change in the recognition properties of CUP2. This variant protein interacts with only one part of the wild-type site and prefers to bind to a different half-site from the wild-type protein. Although the variant has about 10% of wild-type DNA-binding activity, it appears to be completely incapable of activating transcription.

Adhesive and Signaling Properties of a Naturally Occurring Allele of Glycoprotein IIIa With an Amino Acid Substitution Within the Ligand Binding Domain—The Pena/PenbPlatelet Alloantigenic Epitopes

Blood ◽  
1998 ◽  
Vol 92 (9) ◽  
pp. 3260-3267 ◽  
Author(s):  
Ronggang Wang ◽  
Peter J. Newman
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Amino Acid Substitution ◽  
Polyclonal Antibodies ◽  
Chinese Hamster ◽  
Binding Domain ◽  
Integrin Subunit ◽  
Adhesive Properties ◽  
Platelet Surface ◽  
Glycoprotein Iiia

Platelet membrane glycoprotein IIIa (GPIIIa) is the most polymorphic integrin subunit in man, with at least seven recognized allelic isoforms present in the human gene pool. Whether these allelic variants of the GPIIb-IIIa complex differ in the ability to interact with the adhesive ligand fibrinogen (Fg) is still unknown. Since the Pena and Penb allelic forms of GPIIIa are distinguished by a single Arg143Gln amino acid substitution within the RGD binding domain of GPIIIa and anti-Pena human alloantibodies have been shown to bind GPIIb-IIIa on the platelet surface and inhibit ADP-induced platelet aggregation, we expressed both forms of this integrin in Chinese hamster ovary (CHO) cells and examined the relative adhesive properties. Both allelic forms of GPIIb-IIIa were expressed on the cell surface and were recognized by a well-characterized panel of murine and human monoclonal and polyclonal antibodies. Like Pena, the Penb form of GPIIb-IIIa could undergo conformational changes in response to RGD peptide binding, and could be induced by activating antibodies to bind Fg and the Fg mimetic antibody P1-55. The binding affinity for Fg of the Pena form of the GPIIb-IIIa complex was not significantly different from that of the Penb form, nor was its ability to signal to focal adhesion kinase, suggesting that Arg143Gln polymorphism has little or no effect on integrin function. Examination of the functional consequences of other integrin polymorphisms may be necessary to determine whether they constitute a risk factor for thrombosis or hemorrhage. © 1998 by The American Society of Hematology.

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