Glycoside hydrolase 131 catalytic N-terminal domain. This is the N-terminal domain found in glycoside hydrolase family 131 (GH131A) protein observed in Coprinopsis cinerea. GH131A exhibits bifunctional exo-beta-1,3-/-1,6- and endo-beta-1,4 activity toward beta-glucan. This domain is catalytic in nature though the catalytic mechanism of C. cinerea GH131A is different from that of typical glycosidases that use a pair of carboxylic acid residues as the catalytic residues. In the case of GH131A, Glu98 and His218 may form a catalytic dyad and Glu98 may activate His218 during catalysis.
N-terminal domain of transcription factor Specificity Protein (SP) 4. Specificity Proteins (SPs) are transcription factors that are involved in many cellular processes, including cell differentiation, cell growth, apoptosis, immune responses, response to DNA damage, and chromatin remodeling. Human SP4 is a risk gene of multiple psychiatric disorders including schizophrenia, bipolar disorder, and major depression. SP4 belongs to a family of proteins, called the SP/Kruppel or Krueppel-like Factor (KLF) family, characterized by a C-terminal DNA-binding domain of 81 amino acids consisting of three Kruppel-like C2H2 zinc fingers. These factors bind to a loose consensus motif, namely NNRCRCCYY (where N is any nucleotide; R is A/G, and Y is C/T), such as the recurring motifs in GC and GT boxes (5'-GGGGCGGGG-3' and 5-GGTGTGGGG-3') that are present in promoters and more distal regulatory elements of mammalian genes. SP factors preferentially bind GC boxes, while KLFs bind CACCC boxes. Another characteristic hallmark of SP factors is the presence of the Buttonhead (BTD) box CXCPXC, just N-terminal to the zinc fingers. The function of the BTD box is unknown, but it is thought to play an important physiological role. Another feature of most SP factors is the presence of a conserved amino acid stretch, the so-called SP box, located close to the N-terminus. SP factors may be separated into three groups based on their domain architecture and the similarity of their N-terminal transactivation domains: SP1-4, SP5, and SP6-9. The transactivation domains between the three groups are not homologous to one another. SP1-4 have similar N-terminal transactivation domains characterized by glutamine-rich regions, which, in most cases, have adjacent serine/threonine-rich regions. This model represents the N-terminal domain of SP4.
Chain A, Crystal structure of the catalytic domain of the glycoside hydrolase family 131 protein from Coprinopsis cinerea [Coprinopsis cinerea okayama7#130],3W9A_B Chain B, Crystal structure of the catalytic domain of the glycoside hydrolase family 131 protein from Coprinopsis cinerea [Coprinopsis cinerea okayama7#130],3W9A_C Chain C, Crystal structure of the catalytic domain of the glycoside hydrolase family 131 protein from Coprinopsis cinerea [Coprinopsis cinerea okayama7#130],3W9A_D Chain D, Crystal structure of the catalytic domain of the glycoside hydrolase family 131 protein from Coprinopsis cinerea [Coprinopsis cinerea okayama7#130]