Import

We will now import the raw data into RELION. In the GUI, select Import from the jobt-type browser on the top left and fill in the following parameters on the General tab:

Tilt image files:

frames/*.mrc

Movies already motion corrected?:

No

(These are 8-frame movies that have not yet been motion-corrected.)

mdoc files:

mdoc/*.mdoc

Optics group name:

optics1

(All imported tomograms will belong to the same optics group with this name. When left empty, each tomogram will be its own optics group, with the tomogram name as the optics group name.)

Prefix:

""

Pixel size (Angstrom)::

0.675

Voltage (kV)::

300

Spherical aberration (mm)::

2.7

Amplitude contrast::

0.1

On the Tilt series tab:

Dose rate per tile-image:

3

Is dose rate per movie frame?:

No

Tilt axis angle (deg):

85

(This is the nominal value for the tilt-axis orientation wrt to the Y-axis (positive is CCW from Y))

MTF file:

""

Invert defocus handedness?:

Yes

(Specify Yes to flip the handedness of the defocus geometry; the default, Yes, leads to a value of -1 in the STAR file, which is the correct one for the tutorial dataset.)

We skip the Coordinates tab for now (we will use it in the Import coordinates section to import particle coordinates obtained from other programs), and on the Running tab set:

Submit to queue?:

No

You may provide a meaningful alias (for example: tilt_series) for this job in the white field named Current job: Give_alias_here. Clicking the Run! button will launch the job.

A directory called ImportTomo/job001/ will be created, together with a symbolic link to this directory that is called ImportTomo/tilt_series. Inside the newly created directory a tilt_series.star file is created. It contains a table with an entry for each tilt series. For each tilt series, a separate starfile contains relevant metadata that has been extracted from the input images and mdoc files. Have a look at these by typing:

less Import/job001/tilt_series.star
less Import/job001/tilt_series/TS_01.star