Jmol/Visualizing large molecules: Difference between revisions
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===62 Chains=== | ===62 Chains=== | ||
In the | In the final update of the PDB data format specification ([https://www.wwpdb.org/documentation/file-format-content/format33/v3.3.html#ATOM Version 3.3]) and the current remediation of PDB data, chain IDs (names) must be single alphanumeric characters (A-Z, a-z, 0-9). This permits a maximum of 62 chains. This limit is not much of a problem for [[asymmetric unit|asymmetric units]]. In January, 2011, there is only one PDB entry with 62 chains ([[2zkr]]), and 4 more with 55-60 chains. | ||
Generally, the first 26 chains are given IDs A-Z. Above 26, it is apparently arbitrary whether numerals or lower case letters are used first. For example, for the 28 chains in [[3krd]] or [[3hln]] or [[3gpt]], those beyond A-Z are 1-2. Alternatively, for the 28 chains in [[3lo3]], the extra two are identified a-b, and in the 42-chain [[3jqo]], lower case ID's are present but no numerals. Also, when numerals are used, they may begin with 1, or with 0 ([[3fic]]). Occasionally, the letters A-Z are not used up before lower case ID's are employed: [[1tzn]] has 28 chains with ID's A-O and a-o. | Generally, the first 26 chains are given IDs A-Z. Above 26, it is apparently arbitrary whether numerals or lower case letters are used first. For example, for the 28 chains in [[3krd]] or [[3hln]] or [[3gpt]], those beyond A-Z are 1-2. Alternatively, for the 28 chains in [[3lo3]], the extra two are identified a-b, and in the 42-chain [[3jqo]], lower case ID's are present but no numerals. Also, when numerals are used, they may begin with 1, or with 0 ([[3fic]]). Occasionally, the letters A-Z are not used up before lower case ID's are employed: [[1tzn]] has 28 chains with ID's A-O and a-o. | ||
