Alexander Wlodawer , Zbigniew Dauter , Pawel Rubach , Wladek Minor , Joanna I. Loch , Dariusz Brzezinski , Miroslaw Gilski , Mariusz Jaskolski
{"title":"Waterless structures in the Protein Data Bank","authors":"Alexander Wlodawer , Zbigniew Dauter , Pawel Rubach , Wladek Minor , Joanna I. Loch , Dariusz Brzezinski , Miroslaw Gilski , Mariusz Jaskolski","doi":"10.1107/S2052252524009928","DOIUrl":null,"url":null,"abstract":"<div><div>A global analysis of protein crystal structures in the Protein Data Bank reveals many medium-to-high-resolution entries that lack any solvent molecules. Also, there are many cases with impossible occupancies of water molecules and/or uninterpreted very high difference electron-density peaks that indicate the presence of unmodeled water molecules.</div></div><div><div>The absence of solvent molecules in high-resolution protein crystal structure models deposited in the Protein Data Bank (PDB) contradicts the fact that, for proteins crystallized from aqueous media, water molecules are always expected to bind to the protein surface, as well as to some sites in the protein interior. An analysis of the contents of the PDB indicated that the expected ratio of the number of water molecules to the number of amino-acid residues exceeds 1.5 in atomic resolution structures, decreasing to 0.25 at around 2.5 Å resolution. Nevertheless, almost 800 protein crystal structures determined at a resolution of 2.5 Å or higher are found in the current release of the PDB without any water molecules, whereas some other depositions have unusually low or high occupancies of modeled solvent. Detailed analysis of these depositions revealed that the lack of solvent molecules might be an indication of problems with either the diffraction data, the refinement protocol, the deposition process or a combination of these factors. It is postulated that problems with solvent structure should be flagged by the PDB and addressed by the depositors.</div></div>","PeriodicalId":14775,"journal":{"name":"IUCrJ","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11533996/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"IUCrJ","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/org/science/article/pii/S2052252524000897","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
A global analysis of protein crystal structures in the Protein Data Bank reveals many medium-to-high-resolution entries that lack any solvent molecules. Also, there are many cases with impossible occupancies of water molecules and/or uninterpreted very high difference electron-density peaks that indicate the presence of unmodeled water molecules.
The absence of solvent molecules in high-resolution protein crystal structure models deposited in the Protein Data Bank (PDB) contradicts the fact that, for proteins crystallized from aqueous media, water molecules are always expected to bind to the protein surface, as well as to some sites in the protein interior. An analysis of the contents of the PDB indicated that the expected ratio of the number of water molecules to the number of amino-acid residues exceeds 1.5 in atomic resolution structures, decreasing to 0.25 at around 2.5 Å resolution. Nevertheless, almost 800 protein crystal structures determined at a resolution of 2.5 Å or higher are found in the current release of the PDB without any water molecules, whereas some other depositions have unusually low or high occupancies of modeled solvent. Detailed analysis of these depositions revealed that the lack of solvent molecules might be an indication of problems with either the diffraction data, the refinement protocol, the deposition process or a combination of these factors. It is postulated that problems with solvent structure should be flagged by the PDB and addressed by the depositors.
期刊介绍:
IUCrJ is a new fully open-access peer-reviewed journal from the International Union of Crystallography (IUCr).
The journal will publish high-profile articles on all aspects of the sciences and technologies supported by the IUCr via its commissions, including emerging fields where structural results underpin the science reported in the article. Our aim is to make IUCrJ the natural home for high-quality structural science results. Chemists, biologists, physicists and material scientists will be actively encouraged to report their structural studies in IUCrJ.