diff --git a/basicrta/cluster.py b/basicrta/cluster.py
index ceee4dd..d0e86d6 100644
--- a/basicrta/cluster.py
+++ b/basicrta/cluster.py
@@ -8,8 +8,18 @@
 from basicrta.gibbs import Gibbs
 gc.enable()
 
+""" This module provides the ProcessProtein class, which collects and processes
+Gibbs sampler data.
+"""
 
 class ProcessProtein(object):
+    r""" ProcessProtein is the class that collects and processes Gibbs sampler
+    data. This class collects results for all residues in the 
+    `basicrta-{cutoff}` directory and can write out a :math:`\tau` vs resid
+    numpy array or plot :math:`\tau` vs resid. If a structure is provided,
+    :math:`\tau` will be written as b-factors for visualization.
+    """
+    
     def __init__(self, niter, prot, cutoff):
         self.residues = {}
         self.niter = niter
@@ -131,7 +141,7 @@ def b_color_structure(self, structure):
     parser.add_argument('--nproc', type=int, default=1)
     parser.add_argument('--cutoff', type=float)
     parser.add_argument('--niter', type=int, default=110000)
-    parser.add_argument('--prot', type=str)
+    parser.add_argument('--prot', type=str, default=None, nargs='?')
     parser.add_argument('--structure', type=str, nargs='?')
     args = parser.parse_args()
 
diff --git a/basicrta/util.py b/basicrta/util.py
index feb68e6..6f2364c 100644
--- a/basicrta/util.py
+++ b/basicrta/util.py
@@ -399,7 +399,7 @@ def make_residue_plots(results, comps=None, show=False):
     plot_trace(r, 'rates', comp=comps, save=True, show=show, yrange=[-0.1, 6])
 
 
-def plot_protein(residues, t_slow, bars, prot, label_cutoff=3, ylim=None,
+def plot_protein(residues, t_slow, bars, prot=None, label_cutoff=3, ylim=None,
                  major_tick=None, minor_tick=None, scale=1):
     with open('tm_dict.txt', 'r') as f:
         contents = f.read()
@@ -412,11 +412,14 @@ def plot_protein(residues, t_slow, bars, prot, label_cutoff=3, ylim=None,
     fig, axs = plt.subplots(2, 1, figsize=(width, height), sharex=True)
     axs[0].tick_params(axis='both', which='major', labelsize=10)
     axs[1].tick_params(axis='both', which='major', labelsize=10)
-    p = [Rectangle((tm(prots[prot]['helices'], i + 1)[0][0], 0),
-                   tm(prots[prot]['helices'], i + 1)[1], 1, fill=True) for i in
-         range(7)]
-    patches = PatchCollection(p)
-    patches.set_color('C0')
+    if prot is not None:
+        p = [Rectangle((tm(prots[prot]['helices'], i + 1)[0][0], 0),
+                       tm(prots[prot]['helices'], i + 1)[1], 1, fill=True) 
+             for i in range(7)]
+        patches = PatchCollection(p)
+        patches.set_color('C0')
+        axs[1].add_collection(patches)
+    
     resids = np.array([int(res[1:]) for res in residues])
     max_inds = np.where(t_slow > label_cutoff * t_slow.mean())
     axs[0].plot(resids, t_slow, '.', color='C0')
@@ -424,22 +427,20 @@ def plot_protein(residues, t_slow, bars, prot, label_cutoff=3, ylim=None,
                     alpha=0.5)
     [axs[0].text(resids[ind], t_slow[ind], residues[ind]) for ind in
      max_inds[0]]
-    axs[1].add_collection(patches)
-    # if (prot=='cck1r') or (prot=='cck2r'):
-    #    axs[0].set_ylim(0, 1300)
-    # else:
-    #    axs[0].set_ylim(0, 500)
     axs[0].set_ylabel(r'$\tau$ [ns]')
     axs[1].set_xlabel(r'residue')
     axs[0].get_xaxis().set_visible(False)
     axs[1].get_yaxis().set_visible(False)
     axs[1].xaxis.set_major_locator(MultipleLocator(100))
-    axs[0].yaxis.set_major_locator(MultipleLocator(major_tick))
+    if major_tick is not None:
+        axs[0].yaxis.set_major_locator(MultipleLocator(major_tick))
+    if minor_tick is not None:
     axs[0].yaxis.set_minor_locator(MultipleLocator(minor_tick))
-    # axs[1].xaxis.set_minor_locator(MultipleLocator(10))
+    if ylim is not None:
+        axs[0].set_ylim(ylim)
     axs[1].set_aspect(7)
     axs[0].margins(x=0)
-    axs[0].set_ylim(ylim)
+
     plt.subplots_adjust(hspace=-0.45, top=0.92)
     sns.despine(offset=10, ax=axs[0], bottom=True)
     sns.despine(ax=axs[1], top=True, bottom=False, left=True)