: Role of individual sugars: exoglycosidases. Particularly useful for exploring the terminalsialic acid: Sialidases (neuraminidases), work on glycansattachedtoproteins: Many glycoforms make separations on a large-enough scale experiments impractical
• Role'of'individual'sugars:'exoglycosidases • Par3cularly'useful'for'exploring'the'terminal' sialic'acid' • Sialidases'(neuraminidases),'work'on'glycans aEached'to'proteins' • Many'glycoforms'make'separa3ons'on'a'largeJ enough'scale'experiments'imprac3cal
: Where proteins can be expressed intransfected cells in tissue culture, mutant celllines that lack specific glycosyltransferasesand glycan-processing enzymes can be used toproduceproteins withaltered sugars: E.g. Glycoproteins that contain only highmannose N-linked oligosaccharides instead ofcomplexglycanscanbeproduced
• Where'proteins'can'be'expressed'in' transfected'cells'in'3ssue'culture,'mutant'cell' lines'that'lack'specific'glycosyltransferases and'glycanJprocessing'enzymes'can'be'used'to' produce'proteins'with'altered'sugars' • E.g.'Glycoproteins'that'contain'only'highJ mannose'NJlinked'oligosaccharides'instead'of' complex'glycans'can'be'produced
2 Sugars stabilize the structure of thecell-adhesion molecule CD2
2 Sugars stabilize the structure of the cell-adhesion molecule CD2
CD2 (cluster of differentiation 2): A cell-adhesion molecule on the surface of killer Tlymphocytes (淋巴细胞)that mediates binding totarget cells: The extracellular portion of the CD2 polypeptideconsists of two domains from the immunoglobulin(兔疫球蛋白)superfamily,that are linked to themembranebyaC-terminal membraneanchor: Counter-receptors for CD2 on target cells, CD58 inhumans and CD48 in mice, have similar overalldomain organization and cell adhesion results frominteractions between the N-terminal IG typedomains
CD2'(cluster'of'differen3a3on'2)'' • A'cellJadhesion'molecule'on'the'surface'of'killer'T' lymphocytes'(淋巴细胞)'that'mediates'binding'to' target'cells' • The'extracellular'por3on'of'the'CD2'polypep3de' consists'of'two'domains'from'the'immunoglobulin(免 疫球蛋白)'superfamily,'that'are'linked'to'the' membrane'by'a'CJterminal'membrane'anchor' • CounterJreceptors'for'CD2'on'target'cells,'CD58'in' humans'and'CD48'in'mice,'have'similar'overall' domain'organiza3on'and'cell'adhesion'results'from' interac3ons'between'the'NJterminal'IG'type'domains
RRRRRSRRRRtuuuisluuu!CD48/CD58ontarget cellSC2CD2onCkillerTcellRRRRRSRRRRuuusuuuuyRCurrentProtein and Peptide Science,2001,2,1-17