1. Protection of Secreted Proteins in Cyanobacteria Aaron Holman

2. How do cells secrete proteins? Most use Sec pathway Some use TAT pathway Signal sequence

3. Why? Harsh conditions inhibit folding Archae, Bacteria (Cyanobacteria)

4. Goals How do cyanobacteria protect secreted proteins? What kind of proteins use the TAT patway?

5. What is the TAT signal? (S/T)RRxFLK………[Non-hydrophobic] QRSKKSRRTFLKKRQQSMAAAAAAAAA

6. Searching for TAT signals Pattern match (S/T)RRXFLK..[Non-Hydrophobic] (PSSM (pattern match RR…[Non-Hydrophobic])) Score = (PSSM/Background) S8102 MIT9313 PCC6803 TRRSFLS..[Non-Hydrophobic] ("TRRDAMA" "GRRRFLR" "SRRQFLT" "DRRRFLT" "TRRDALR" "TRRGFLK" "TRRSFLK" "DRRTFMK" "SRRDFMK" "NRRNFIK" "TRRDFLY" "GRRQFMN" "DRRTFLR" "SRRAFLS" "TRREFIK" "SRRDLLK" "DRRKFLK" "SRRGLVK" "SRRDFVK" "SRRSFLQ" "SRRGFLV" "SRRGFLV" "SRRGFLG" "SRRTFVK" "SRRQFIQ" "SRRGFIG" "NRRDFIK" "SRRRFLA") 0.51724136 / 0.058600802 = 8.826524

7. Observations (#$S8102.p-SynW0321 20.450802 "ABC transporter, membrane component")#$S8102.p-SynW0321 (#$S8102.p-SynW0924 19.10863 "ABC transporter, multidrug efflux family")#$S8102.p-SynW0924 (#$S8102.p-SynW1023 16.258312 "ABC transporter, multidrug efflux family")#$S8102.p-SynW1023 (#$S8102.p-SynW0825 17.05498 "ABC transporter, possibly multidrug efflux")#$S8102.p-SynW0825 A sample of the results sorted by description S8102- Total 1083ABC transporter 53 Mit9313- Total 898ABC transporter 46 PCC6803- Total 1221 ABC transporter 29

8. ABC Transporter Proteins? Transport system 983 total 473 use TAT

9. Possible Conclusions How do cyanobacteria protect secreted proteins? TAT pathway What kind of proteins use the TAT patway? ABC transporters

10. Thanks to Brian Palenik