In search for improvement of our current YAC end rescue protocols I asked Herve Tettelin to generated a table containing all possible hexamers and their frequencies in P. falciparum genome, using our current 1,300.000 sequence reads for chromosome 2. One very useful information we can derive from this table is the occurance of a particular restriction enzyme recognition sequence and its representation in the P. falciparum genome, enabling us to select frequent and rare cutters for different purposes. An immediate application of this data is the selection of enzymes that cut well Pf DNA for YAC end rescue (Riley's method, Nucleic Acids Res. 18:2887-2890, 1990). While working at the human genome project I used to use Alu I and Rsa I and would rescue 95% of human YAC ends. For P. falciparum I have tried Alu I, Rsa I, Dra I, Asn I, Ssp I and Swa I. So far I was able to rescue 14 out of 24 ends with enzymes selected from our hexamer table data. Since I think this is a very useful information to assist in the YAC end rescue protocols and other applications, I want to share it with the group. I have listed 30 enzymes with frequencies from 1 site every 300 bp to 6-8 kb. See attachment Enz/Pfalc/Hex. I will generate a table with rare cutter sequences and their frequencies and share it too. The column "occurance" means how many sites that particular hexamer appears in the genome and "average cut" means its frequency, supposing an even distribution in the 1,300.000 bp. Hope this information will assist other groups in the isolation of terminal sequences from YACs,
| MANUFACT | ENZYME | SEQUENCE | OCCURANCE | AVER. CUT | ENDS | ISOSCHIZOMER | HEAT INACT | TEMPERATURE |
| GIBCO | Acc I | GTATAC | 323 | 4,319 | cohesive | n.a. | resist | 55 |
| " | Afl II | CTTAAG | 270 | 5,167 | cohesive | Bfr I | part. res. | 37 |
| " | Alu I | AGCT | 247 | 5,648 | blunt | n.a. | sens. | 37 |
| BMB | Asn I | ATTAAT | 2,852 | 489 | cohesive | n.a. | ? | ? |
| GIBCO | Bcl I | TGATCA | 384 | 3,644 | cohesive | n.a. | res. | 50 |
| GIBCO | Bgl II | AGATCT | 160 | 8,718 | cohesive | n.a. | res. | 37 |
| GIBCO | Cla I | ATCGAT | 152 | 9177 | cohesive | yes/ >1 | part. res. | 37 |
| GIBCO | Dra I | TTTAAA | 3,539 | 394 | blunt | Aha III | sens. | 37 |
| GIBCO | EcoR I | GAATTC | 254 | 5492 | cohesive | n.a. | part. res. | 37 |
| GIBCO | EcoR V | GATATC | 202 | 6,906 | blunt | sens. | 37 | |
| GIBCO | Hinc II | GTPyPuAC | n.a. | n.a. | blunt | Hind II | sens. | 37 |
| GIBCO | Hae III | GGCC | 54 | 25,833 | blunt | yes/ >1 | res. | 37 |
| GIBCO | Hind III | AAGCTT | 207 | 6,739 | cohesive | n.a. | res. | 37 |
| Pharmacia | Hpa I | TTAAC | more | more | cohesive | ? | ? | ? |
| Pharmacia | same | TTAACA | 887 | 1,573 | ||||
| " | same | TTTAAC | 645 | 2,163 | ||||
| " | Mbo I | GATC | 168 | 8,303 | blunt | yes/ >1 | sens. | 37 |
| GIBCO | Mun I | CAATTG | 207 | 6,739 | cohesive | n.a. | ? | ? |
| BMB | Msc I | TGGCCA | 40 | 34,874 | blunt | BalI,Mlu N I | sens. | 37 |
| GIBCO | Mse I | TTAA | more | more | cohesive | Tru91 I | part. res. | 37 |
| GIBCO | same | TTTTAA | 4,063 | 343 | ||||
| " | same | TTAAAA | 3,890 | 359 | ||||
| " | same | TTTAAA | 3,539 | 394 | ||||
| " | Nde I | CATATG | 776 | 1,798 | cohesive | ? | ? | ? |
| Pharmacia | Sfu I (Asu II) | TTCGAA | 208 | 6,707 | cohesive | ? | ? | ? |
| BMB | Nsp V | same | 208 | 6,707 | cohesive | yes/ >1 Sfu I | part. res. | 50 |
| GIBCO | Pst I | CTGCAG | 64 | 21,796 | cohesive | n.a. | part. res. | 37 |
| GIBCO | Rsa I | GTAC | 206 | 6,772 | blunt | Csp 6 | sens. | 37 |
| GIBCO | Sal I | GTCGAC | 37 | 37,702 | cohesive | n.a. | res. | 37 |
| GIBCO | Taq I | TCGA | cohesive | TthHB8 I | res. | 65 | ||
| GIBCO | " | TCGAA | 215 | 6,488 | ||||
| TTTCGA | 214 | 6,518 | ||||||
| ATCGA | 211 | 6,611 | other possible | sites with | smaller freq. | |||
| GIBCO | Sna BI | TACGTA | 200 | 6,975 | blunt | ? | ? | ? |
| GIBCO | Vsp I | ATTAAT | 2,852 | 489 | cohesive | yes/ >1 | res. | 37 |
| GIBCO | Ssp I | AATATT | 4,595 | 304 | blunt | ? | ? | ? |
| BMB | Swa I | ATTTAAAT | more | more | blunt | ? | ? | ? |
| BMB | same | ATTTAA | 2,911 | 479 | ||||
| same | TTAAAT | 2,820 | 495 |
Last Updated: 30/7/97
Analyst/Contact: Robert Huestis
E-Mail Address: robert.huestis@med.monash.edu.au