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Crystal structure of SRCRD11 of human DMBT1 from needle-shape crystal
Structural highlights
DiseaseDMBT1_HUMAN The gene represented in this entry is involved in disease pathogenesis. Homozygous deletions may be the predominant mechanism of DMBT1 inactivation playing a role in carcinogenesis. DMBT1 is deleted in medulloblastoma and glioblastoma cell lines; point mutations have also been reported in patients with glioma. A loss or reduction of DMBT1 expression has been seen in esophageal, gastric, lung and colorectal carcinomas as well. FunctionDMBT1_HUMAN May be considered as a candidate tumor suppressor gene for brain, lung, esophageal, gastric, and colorectal cancers. May play roles in mucosal defense system, cellular immune defense and epithelial differentiation. May play a role as an opsonin receptor for SFTPD and SPAR in macrophage tissues throughout the body, including epithelial cells lining the gastrointestinal tract. May play a role in liver regeneration. May be an important factor in fate decision and differentiation of transit-amplifying ductular (oval) cells within the hepatic lineage. Required for terminal differentiation of columnar epithelial cells during early embryogenesis. May function as a binding protein in saliva for the regulation of taste sensation. Binds to HIV-1 envelope protein and has been shown to both inhibit and facilitate viral transmission. Displays a broad calcium-dependent binding spectrum against both Gram-positive and Gram-negative bacteria, suggesting a role in defense against bacterial pathogens. Binds to a range of poly-sulfated and poly-phosphorylated ligands which may explain its broad bacterial-binding specificity. Inhibits cytoinvasion of S.enterica. Associates with the actin cytoskeleton and is involved in its remodeling during regulated exocytosis. Interacts with pancreatic zymogens in a pH-dependent manner and may act as a Golgi cargo receptor in the regulated secretory pathway of the pancreatic acinar cell.[1] [2] [3] [4] [5] [6] [7] [8] Publication Abstract from PubMedScavenger receptors are a protein superfamily that typically consists of one or more repeats of the scavenger receptor cysteine-rich structural domain (SRCRD), which is an ancient and highly conserved protein module. The expression and purification of eukaryotic proteins containing multiple disulfide bonds has always been challenging. The expression systems that are commonly used to express SRCRD proteins mainly consist of eukaryotic protein expression systems. Herein, we established a high-level expression strategy of a Type B SRCRD unit from human salivary agglutinin using the Escherichia coli expression system, followed by a refolding and purification process. The untagged recombinant SRCRD was expressed in E. coli using the pET-32a vector, which was followed by a refolding process using the GSH/GSSG redox system. The SRCRD expressed in E. coli SHuffle T7 showed better solubility after refolding than that expressed in E. coli BL21(DE3), suggesting the importance of the disulfide bond content prior to refolding. The quality of the refolded protein was finally assessed using crystallization and crystal structure analysis. As proteins refolded from inclusion bodies exhibit a high crystal quality and reproducibility, this method is considered a reliable strategy for SRCRD protein expression and purification. To further confirm the structural integrity of the refolded SRCRD protein, the purified protein was subjected to crystallization using sitting-drop vapor diffusion method. The obtained crystals of SRCRD diffracted X-rays to a resolution of 1.47 A. The solved crystal structure appeared to be highly conserved, with four disulfide bonds appropriately formed. The surface charge distribution of homologous SRCRD proteins indicates that the negatively charged region at the surface is associated with their calcium-dependent ligand recognition. These results suggest that a high-quality SRCRD protein expressed by E. coli SHuffle T7 can be successfully folded and purified, providing new options for the expression of members of the scavenger receptor superfamily. Refolding, Crystallization, and Crystal Structure Analysis of a Scavenger Receptor Cysteine-Rich Domain of Human Salivary Agglutinin Expressed in Escherichia coli.,Zhang C, Lu P, Wei S, Hu C, Miyoshi M, Okamoto K, Itoh H, Okuda S, Suzuki M, Kawakami H, Nagata K Protein J. 2024 Apr;43(2):283-297. doi: 10.1007/s10930-023-10173-x. Epub 2024 Jan , 24. PMID:38265733[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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