1. Use "WordPad" to open PDB file, check the part of Atom:

2. PDB的Atom命名方式, CA表示α-碳原子, CB表示β-碳原子, 依此類推。 例如:

• CG, CD, CE, CZ, CH (gamma, delta, epsilon, zeta, eta)
• N7 (7th nitrogen in a residue)
• O2P (second oxygen on a phosphorus)
• OE2 (second oxygen on an epsilon carbon)
• HD1 (1st hydrogen on a delta carbon)

• 相關敘述可以參考http://www.umass.edu/microbio/rasmol/seleccmd.htm#atnames
  PDB files name each atom in a standardized way (up to 4 characters). Alpha-carbons are CA, beta-carbons CB, and so forth through CG, CD, CE, CZ, CH (gamma, delta, epsilon, zeta, eta). Other examples are N7 (7th nitrogen in a residue), O2P (second oxygen on a phosphorus), OE2 (second oxygen on an epsilon carbon), HD1 (1st hydrogen on a delta carbon).

3. 可以使用 Rasmol or PyMOL去確認相關atom的名稱 (Click it!):

4. For your information:

Letter	Name
Α α	alpha
Β β	beta
Γ γ	gamma
Δ δ	delta
Ε ε	epsilon
Ζ ζ	zeta
Η η	eta