Disease relevance of Ngly1

• PNG1 encodes a soluble protein that, when expressed in Escherichia coli, exhibited PNGase activity [1].
• To characterize the dual role of HR23, we have determined the high resolution crystal structure of the mouse peptide N-glycanase catalytic core in complex with the xeroderma pigmentosum group C binding domain from HR23B [2].
• Treatment of 3H-labeled immunoprecipitated melanoma PAA with alkaline-borohydride, hydrazinolysis, or N-glycanase released three families of carbohydrate chains (I, II, and III) [3].
• One of these, PNGase F, is a glycosidase specific for N-linked glycans, and the other, ST-Siase(2,3) from Salmonella typhimurium, is specific for alpha2,3-linked terminal sialic acid residues [4].
• Treatment of synaptic membranes with proteinase K and Staphylococcus aureus V-8 proteinase, a combination of PNGase F and neuroaminidase, heat or acid lowered the 125I-ammodytoxin A specific binding to various extents but never completely abolished it [5].

High impact information on Ngly1

• MAdCAM-1 isolated from mesenteric lymph nodes, but not from cultured endothelioma cells, bears N-glycanase-resistant sialic acid-containing carbohydrate which supports adhesion of L-selectin-transfected lymphoid cells under shear [6].
• However, it is pronase sensitive and dependent on N-linked glycosylation of CD5, since treatment of CD5Rg with PNGaseF on N-glycanase completely abrogates its ability to bind activated splenocytes [7].
• The amino acid substitutions and differences in the number of potential N-linked glycosylation sites probably account for the different forms of neutrophil FcR III observed after digestion with N-glycanase and for the antigenic heterogeneity of this receptor [8].
• In this pathway the cytosolic peptide-N-glycanase (PNGase) cleaves the N-linked glycan chains off denatured glycoproteins [9].
• In higher eukaryotes, PNGase has an N-terminal and a C-terminal extension in addition to its central catalytic domain, which is structurally and functionally related to transglutaminases [9].

Biological context of Ngly1

• Mouse Ngly1 spans 61kb and is composed of 12 exons, the organization of which is conserved throughout vertebrates [10].
• To begin to address this question, we used radiation hybrid mapping to localize mouse Ngly1 to chromosome 14 and the human orthologue to chromosome 3 with a strong link with known genes [10].
• Given the key role Ngly1 plays in glycoprotein degradation, we predict that Ngly1 may be a contributing factor in "disease" susceptibility [10].
• Recently the deduced amino acid sequence of a cytoplasmic PNGase has been identified in various eukaryotes ranging from yeast to mammals, suggesting that deglycosylation may play a central role in some catabolic process [11].
• When gp44 was sequentially treated with N-glycanase and neuraminidase, it lost platelet aggregation activity [12].

Anatomical context of Ngly1

• A 2.6kb Ngly1 message was detected in all mouse tissues examined, with the highest abundance in the testis [10].
• Peptide:N-glycanase (PNGase) is ostensibly the sole enzyme responsible for deglycosylation of unfolded N-linked glycoproteins dislocated from the ER to the cytosol [13].
• These differ with respect to their apparent molecular masses after digestion with N-glycanase, and with respect to their reactivity with MAb Gran 11 and alloantisera which recognize determinants (NA1 and NA2) of the biallelic neutrophil antigen (NA) system [8].
• This size difference was due to altered carbohydrate composition, as N-glycanase digestion reduced the apparent receptor subunit size of the transfected cells and IM-9 lymphocytes to identical values [14].
• N-linked glycans, obtained from N-glycanase-treated IgD and purified by binding to GS-1-Sepharose, also inhibit rosette formation of T-helper cells bearing receptors for IgD with IgD- or mutant IgD-coated erythrocytes [15].

Associations of Ngly1 with chemical compounds

• Remarkably, proteasome-mediated turnover of class I MHC heavy chains proceeds even when PNGase is completely inhibited, suggesting that the function of PNGase may be to facilitate more efficient proteasomal proteolysis of N-linked glycoproteins through glycan removal [13].
• No reactions were observed with dp72 and lectins in Western blots; and neither tunicamycin, N-glycanase, endoglycosidase H nor F affected the migration of [35S]-methionine-labeled protein on SDS-PAGE [16].
• Deglycosylation experiments with N-glycanase and endoglycosidase H indicated that the S-MBP ligands on thymic CD45 are high mannose type or hybrid type N-linked oligosaccharides [17].
• The minimum structural requirements for inhibition of the PNGase activity were Man3 and GlcNAc2 [18].
• Peptide N-glycanase features a large cleft between its catalytic cysteine protease core and zinc binding domain [2].

Other interactions of Ngly1

• The higher m.w. form was glycosylated based on its sensitivity to n-glycanase and displayed a m.w. consistent with that of TNF-beta (LT) [19].
• Serial partial deglycosylation of cross-linked NMB-Rs with PNGase F treatment for different incubation periods revealed one band of partially glycosylated receptor (53 kDa) besides the fully glycosylated and fully deglycosylated ones, showing that NMB-R has two oligosaccharide chains [20].
• After the WGL eluates for the four species were treated with N-Glycanase, the labeled receptors became much sharper bands with very similar molecular masses, i.e., 43 kDa for the cow and guinea pig, 39 kDa for the rat, and and 40 kDa for the mouse.(ABSTRACT TRUNCATED AT 400 WORDS)[21]
• Differential susceptibility to N-glycanase at the individual glycosylation sites of mouse thyrotropin and free alpha-subunits [22].
• Enzymatic removal of preformed carbohydrate chains with N-glycanase had little or no effect on the MAb-reactivity of epitopes V and VII, indicating that the carbohydrate chains per se do not influence the antigenic specificity of VSV-NJ G protein [23].

Analytical, diagnostic and therapeutic context of Ngly1

• After treatment of KCA-3 with N-glycanase, there was no significant change in the m.w., indicating KCA-3 was not highly glycosylated [24].
• Immunoprecipitation from cell lysates (Jurkat, SupT1, PBMC, MonoMac) with the JKT.M1 mAb yields a 20-kDa Ag with few if any carbohydrate residues as determined by N-glycanase and neuraminidase treatments [25].
• Tryptic fragments of the digestion products were then analyzed by reverse phase HPLC so that the effects of N-glycanase at the individual glycosylation sites could be determined [22].
• The glycosylation status of the E protein of each virus was also determined by N glycosidase F (PNGase F) digestion and limited sequence analysis [26].
• Further, the PNGase F released oligosaccharides were derivatized with 9-aminopyrene 1,4,6-trisulfonic acid (APTS) and analyzed by capillary electrophoresis with laser induced fluorescence detection (CE-LIF) [27].

References