04.11.2014 Views

trans

trans

trans

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

VSG Signal sequence Amino-terminal domain Carboxy-terminal domain<br />

T. brucei<br />

MITat1.4 MDCHTKETLGVTQWRRSTMLTLSLLYAITPADG A | | | RHGTEADFDAGAGPAESEVADSGFAQVPGKQDGANAGQANM | |<br />

MITat1.2 MPSNQEARLFLAVLVLAQVLPILVDS A QVSEELDDQPKGALFTLQAAASKIQKMRDAALRASIYAEINHGTNRAKAAVIVANHYAMKADSGLEALKQTLSSQEVTATATASYLKGRIDEYLNLLLQTK| | | † SRA MPRNSGRTTSTLALAVALKLLAVPVSPSGT A | FDEEPVKKV † | | | † STAQTQKLKEKILNTLVPKLVEGSKSQVKLRILKYPGKIQKSKLVSIQELKTRVEPESST |<br />

MITat1.5 MIHSNKVATVVLALISSWPADG T KVEKNLADVAGIALAKINNLIKQVSAATEAEARMTLAAASTDHS | ISALYAAASNIVTR † | VLNAVHALTSLAPIALTAATNGAKTSGHISEVIDILQQASQGKTEGK † IVKSGGGTTTVAIRQLYNKIGDLEKQTTNN | | | | †<br />

HAAVKAAQDMKADPALKVDQTLLAVLVASPEMAEILKLEAAASQQKGPEEVTIDLATEKNNYFGTNNNKLEPLWTKIKGQNIVDLAATKGSTKELGTVTDTAELQKLLSYYYTVNKEEQKK<br />

MMDTSGTNTVTKAGGTIGGVP KLQLSPIQPKRPAATYLGKAGYVGLTRQADAANNFHDNDAE RLASGHNTNGLGKSGQLSAAVTMAAGYVTVANSQTAVTVQALDALQEASGAAHQPWIDAWKAKKALTGAET ETAGIAGKTGVTKLVEEALLKKKDSEASEIQTELKKYFSGHENEQWTAIEKLISEQPVAQNLVGDNQPTKLGELEGNAKLTTILAYYRMETAGKFEV<br />

KMSKELKATAMRAANDAKLKITEILELENVFAAMIP ATKGTEADG TDYNAVFLEA NTAAETVSKIATLAESATKAAGAAGRAAGVLDEFIAALAQAQGAT IQGSGTGAATHTELAD FNGDLKPRNMLSIRDPKVSAAATGSTDLTTLAKAMAASGTDTTFHGDQQSKG GLMKGTSDGIMIGQALTGTFAWAQGLLRFGALGANGIASTGVTGYAHTATASGNGVHWASDPEKIPVIAEAIALVSNYNTLADSIGTRAKDAI MKATNKEIKREHIFL VSHLNRELQKAVTELDKALNK<br />

NKISEEPK |<br />

|<br />

DDKKQIE<br />

†<br />

| KF STKAKEKGVSVTQTQTAGGTEATTDK| KGKLEDT | | | K<br />

NKKDQNE | | TLDKEEAKKVADETAKDGKTGNT†<br />

| | | |<br />

NAIGDDKDK KGKLEPG TKAQEYEWEGKESK<br />

| | | |<br />

TQHGTNKEA GFRKGKDGETDEPDKEK|<br />

ILTat1.25 MQSQQQPVFISIILLAINTDAA A | | | † | |<br />

L<br />

LOUTat1.5 MQQSRSRTPTCSKNCTLKALFITVATLILAPKTSD A | | | † | |<br />

L<br />

| | | | †<br />

DGSEANGKGS VILSTSASKYKVETPDWLNALEAAIADLEQEQIELDNGRKAEAQILAL<br />

EPTKQPPAKAAAAPEKKSNPQKD<br />

| | | | |<br />

QT DGSSTA A VYLGANGDAPNKP TWLDELTQALLAAQTAA<br />

PTTAVNAREFGLL TLVRAEDNLEDRRSAGQAAKEVVALAAKIELILANLKHIERLAAAEPEAAPKESRSDETPEA KASKATV SQAAQTYKTIRPDEKLALAFLAETTGDLRSTF VTLKQITAAAASHARYFGENTESRPALDKIKKALYGSPEAKGDAIIESGDGT GNTDGNAANSAAKRATAALI GGDNTNTGNDA FTQTTADINYAKKGGEVERAWTEIRQK KAGAAANKVTAAQLKAAAAELAALIHQKRGEKAVAGLLGAAQINND<br />

AAATAGSNSAVFQHL TLVNAVTEVEKVGDVPATVTQIHAIAERTALIFRAAKELEELAAQTPGTTKKEVAPKKPNTI TERLKDA DKAATYLKQMMPQDRQHLLAFVASSDPTVQLV DTANSLLLKTSNFIADAKKRSNKEVLKHLRTALYSEGKDSVTNAIFTATSGR GSQSGGAAKGAKNNLAATLL AGDSTN DNEAVPAVTFNKNGNDAASAFEKIRTI KRRAETPTLSRLPQAIAAAIGAVTADLAAPKGDNPDVGTIGGITTGGRPD<br />

SSXTTLLAQAV<br />

| | | |<br />

TWLDELTQALLAAQTAAKAELDSTAQAAHIEGI†TTLALALLNGIYQTQANSRQQTHQEAPQHPREHMANSAKT|<br />

EQHKGnKTA<br />

|<br />

|<br />

|<br />

|<br />

|<br />

EAKGGEDGVKAANDGKST†TTGN<br />

T. congo MIKVLLTLLSVAVCQKGLT S | † | | | | | † | | |<br />

GELDNVQEFGIL RIYQIASTTVPEASSAHDGQMTKLMKDISDIVLSTTA DSYYEAESTKITPNIKEH KRISASSQTQPLVRKMRRILARASARAAELGSLGKEDQSARDTIRKALLKAIYGKDVDTQEDGEAAVRGAEAPVFGDQKSKLGS GGSGGPSTGEHVGVSLVNDFF L IAGGHSAGDKW HISIAKASANKNWASLTGHDTEWGKIKTN PRFSV LTASAIDQALMAFHSRLGGGGKGTPNGDSGQQIGGYIFGKTGTLA TGDDGQV LNYKKNLVPESNGKIKGIDWEKRLREASWELRQIEERKREGEVLLTQLEMLNHSAW LEAWDRVEDER<br />

SSSTKVSGSPEGDKGTTKTPIS†GSLPI<br />

E<br />

AEGGNAAEFQLL DAARLAAAMATGKERSMLATTGSPESVARVEVGQGLIGAALEAWLNGQSDEADKKIAEETASRMTEASQTHSDALKAALTAAEAHARSQAQSKQAEAKKLAAQALGVDEGT LTITQSSTKGEQKWTSSAPASYA KTQAQNE LKGLVSSNDIAQNNAVEKWETDIKTRIDKP C T. vivax ..DWGGDNAENIGACSVWLLFARHAE | | | TTHAGKIAGDIMYL | | | LAGDHTGIEVTLDAVDTAIGRIRAAVGTKSGKDKFGSDSSTTLTYTAAFATNGNGNEGEHFWGKKLKQAATHLAQARQALAFAQEMQARKRKIENTERLVGDPLAETKTRRAAKEQTATEAQKRDHQ<br />

GNEDMSTRETGKK<br />

FIGURE 5.3 Conserved features of typical VSG sequences. VSG amino-terminal domains fall into two major classes, having either 4–6 or 10–12<br />

cysteine residues (indicated by vertical bars). Carboxy-terminal subdomains contain two disulfide bonds and T. brucei<br />

or two subdomains. All seven sequenced T. congolense VSGs have a similar structure to the one example shown, but do not contain the carbo<br />

terminal subdomain found in T. brucei VSGs. The single known T. vivax VSG also lacks the carboxy-terminal domain and is distinguished b<br />

absence of N-glycosylation sites. Disulfide linkages have been experimentally determined for one T. brucei and one T.<br />

by the overlines) but cysteine residues are so highly conserved that they are likely to adopt the same pairing in all VSGs<br />

sequences indicate the boundary between amino- and carboxy-terminal domains, based on crystal structures or by<br />

carboxy-terminal signal sequences highlight the extraordinary conservation of VSG GPI signal sequences, where a br<br />

the hydrophobic domain, to emphasize the conserved bipartite motif. The carboxy-terminal GPI attachment sites have been exper<br />

determined for MITat 1.2, 1.4 & 1.5 and are predicted for the other sequences, which are highly conserved in<br />

T. congolense. The mature amino-termini were experimentally determined for all sequences except VSG ILTat1.25 and SRA, which w<br />

predicted using SignalP. † indicates probable N-glycosylation sites. These have been experimentally verified for MITat 1.2, 1.4 & 1.5. S<br />

N-glycosylation sites within disulfide-linked regions of carboxy-terminal subdomains of some VSGs are not marked as they ar<br />

cosylated, because of accessibility constraints. SRA is the VSG-like molecule that can confer human infectivity on T. brucei<br />

|<br />

|<br />

|<br />

|<br />

NKNTKKRD<br />

NEDKI<br />

GDTPG<br />

KEGDG<br />

SWHKEVKAGEKH|<br />

GWHKAEGK<br />

KWSSTEATEGAF<br />

NnETR<br />

EAKDGEGQKNQATGEKDANKNR|<br />

SYDDSKGSDKK<br />

KPKDGEGQTSAAGAGDAGASDTEAKK<br />

KSP<br />

TYNAEKAEANGAPATQPQGGVNEATTGN|<br />

TEAK<br />

|<br />

KWHNDAENKK<br />

EKENTPGQSAV<br />

SDKKKEEE<br />

KWKGGDDEKGE|<br />

KKESN<br />

KSPN<br />

|<br />

KWENNA<br />

KWDGKE<br />

TGS

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!