Thanks all for information and tips. With the help, I did some quick'n dirty analysis
Total PDB (2011-01-11) 70303 Method Xray 61092 HHHHH 10060 Method Xray and HHHHH 9098 TEV-recognition HHHHHX{0,30}ENLYFQ 918 Method Xray and HHHHHX{0,30}ENLYFQ 877 Method Xray and ENLYFQ X{0,30} HHHHH 26 EK recognition HHHHHX{0,30}DDDDK 126 Method Xray and HHHHHX{0,30}DDDDK 117 DDDKX{0,30}HHHHH 14 Method Xray and DDDKX{0,30}HHHHH 14 Thrombin HHHHHX{0,30}LVPRGS 1519 Method XRAY and HHHHHX{0,30}LVPRGS 1400 LVPRGSX{0,30}HHHHH 37 XRAY and LVPRGSX{0,30}HHHHH 35 3C HHHHHX{0,30}LE[VAT]LFQGP 42 XRAY and HHHHHX{0,30}LE[VAT]LFQGP 40 LE[VAT]LFQGPX{0,30}HHHHH 1 XRAY and LE[VAT]LFQGPX{0,30}HHHHH 1 Xa HHHHHX{0,30}I[ED]GR 89 XRAY and HHHHHX{0,30}I[ED]GR 75 I[ED]GRX{0,30}HHHHH 41 XRAY and I[ED]GRX{0,30}HHHHH 36 XRAY and not any of the above patterns 6477 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Actually, typically we set up crystal trials for both cleaved and uncleaved protein right away at the same time (if there's enough protein and the cleavage works). Cheers phx >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> On 07/01/2011 15:10, Bosch, Juergen wrote: I vaguely remember a paper by Aled Edwards, where they did the statistics for their targets at SGC. As far as I recall they engineer with cleavable tag purify and cyrstallize it first with tag and only if they don't get crystals or a structure they cleave off the tag and rerun the screens. I think the numbers where 30% of the proteins have been cleaved. Jürgen >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> "Carson, M. et al. (2007). His-tag impact on structure. Acta Crystallographica Section D 63, 295-301". A contribution I made to a thread on the CCP4 emails (I can give you a link to the archive if you want to find it and don't) was: "As at 2 January 2006 there were 236 structures with at least one chain containing 5 or more consecutive Histidine residues. Atom records were used in order to extract out the sequences of the polypeptides. ..... Erdahl Teber >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Reference from Wladek Minor (Kirillova, Acta Cryst D63, 2007, 348-354), this structure shows an ordered 10 residue segment from an uncleaved tag including TEV recognition site. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Dear Arjan, Try the Hampton Research website (www.hamptonresearch.com). They have done surveys of the crystallization community about his-tag on or off and the results should still be there. Good luck. Bryan >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Hi Arjan - Since sequence searches of the PDB use the SEQRES records (which are supposed to represent the crystallization construct) rather than the deposited coordinates, you should be able to craft a Blast search with tight enough restraints that searching for 'HHHHHH' or some of the most common protease sites will give you a useful answer. Using NCBI's Blast page, and searching the PDB for an 8-His sequence, I got 205 hits (but there were probably more, and I hit some sort of cap). Hope that helps, Matt >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> The RCSB PDB site (www.pdb.org) provides as sequence motif search as an advanced search option. For example to search for a N-terminal (His)6 tag, use the following regular expression: ^HHHHHH or HHHHHH to find any sequence with a (His)6 pattern. Click on this link to retrieve all sequences with a (His)6 pattern: http://www.pdb.org/pdb/search/smart.do?smartSearchSubtype_0=MotifQuery&motif_0=HHHHHH For more details about the sequence motif search are available at: http://www.pdb.org/pdb/staticHelp.do?p=help/advancedsearch/sequenceMotif.html Best regards, Peter Rose RCSB PDB -------------------------------------------------------------------------- Confidentiality Notice: This message is private and may contain confidential and proprietary information. If you have received this message in error, please notify us and remove it from your system and note that you must not copy, distribute or take any action in reliance on it. Any unauthorized use or disclosure of the contents of this message is not permitted and may be unlawful.