diff --git a/Bio/Cluster/clustermodule.c b/Bio/Cluster/clustermodule.c
index 29b2a5c24ae..5d3c2f7096f 100644
--- a/Bio/Cluster/clustermodule.c
+++ b/Bio/Cluster/clustermodule.c
@@ -1132,7 +1132,7 @@ static PyMethodDef PyTree_methods[] = {
     {"scale", (PyCFunction)PyTree_scale, METH_NOARGS, PyTree_scale__doc__},
     {"cut", (PyCFunction)PyTree_cut, METH_VARARGS, PyTree_cut__doc__},
     {"sort", (PyCFunction)PyTree_sort, METH_VARARGS, PyTree_sort__doc__},
-    {NULL}  /* Sentinel */
+    {NULL, NULL, 0, NULL}  /* Sentinel */
 };
 
 static char PyTree_doc[] =
diff --git a/Bio/Nexus/cnexus.c b/Bio/Nexus/cnexus.c
index 9da632326b4..4787c6cd348 100644
--- a/Bio/Nexus/cnexus.c
+++ b/Bio/Nexus/cnexus.c
@@ -103,10 +103,10 @@ static PyObject * cnexus_scanfile(PyObject *self, PyObject *args)
     }
 }
 
-static PyMethodDef cNexusMethods[]=
+static PyMethodDef cNexusMethods[] =
 {
     {"scanfile",cnexus_scanfile,METH_VARARGS,"Scan file and deal with comments and quotes."},
-    {NULL,NULL,0,NULL}
+    {NULL, NULL, 0, NULL}
 };
 
 static struct PyModuleDef moduledef = {
diff --git a/Bio/PDB/ccealignmodule.c b/Bio/PDB/ccealignmodule.c
index 2704b763ae0..c15c4069ba4 100644
--- a/Bio/PDB/ccealignmodule.c
+++ b/Bio/PDB/ccealignmodule.c
@@ -619,7 +619,8 @@ Arguments:\n\
 
 static PyMethodDef CEAlignMethods[] = {
     {"run_cealign", PyCealign, METH_VARARGS, method_doc},
-    {NULL, NULL, 0, NULL}};
+    {NULL, NULL, 0, NULL}
+};
 
 PyDoc_STRVAR(module_doc,
 "Pairwise structure alignment of 3D structures using combinatorial extension.\
diff --git a/Bio/PDB/kdtrees.c b/Bio/PDB/kdtrees.c
index 3f165cf2633..1709a9c3671 100644
--- a/Bio/PDB/kdtrees.c
+++ b/Bio/PDB/kdtrees.c
@@ -1318,7 +1318,7 @@ static PyMethodDef KDTree_methods[] = {
      (PyCFunction)PyKDTree_neighbor_simple_search,
       METH_VARARGS,
       PyKDTree_neighbor_simple_search__doc__},
-    {NULL}  /* Sentinel */
+    {NULL, NULL, 0, NULL}  /* Sentinel */
 };
 
 PyDoc_STRVAR(KDTree_doc,
diff --git a/Bio/SeqIO/_twoBitIO.c b/Bio/SeqIO/_twoBitIO.c
index c08993297a0..504187f5e5d 100644
--- a/Bio/SeqIO/_twoBitIO.c
+++ b/Bio/SeqIO/_twoBitIO.c
@@ -457,7 +457,7 @@ static struct PyMethodDef _twoBitIO_methods[] = {
      METH_VARARGS | METH_KEYWORDS,
      TwoBit_convert__doc__
     },
-    {NULL,          NULL, 0, NULL} /* sentinel */
+    {NULL, NULL, 0, NULL} /* sentinel */
 };
 
 
diff --git a/Bio/motifs/_pwm.c b/Bio/motifs/_pwm.c
index e29123b7649..2865e0f2dcd 100644
--- a/Bio/motifs/_pwm.c
+++ b/Bio/motifs/_pwm.c
@@ -194,7 +194,7 @@ static struct PyMethodDef methods[] = {
     METH_VARARGS | METH_KEYWORDS,
     PyDoc_STR(calculate__doc__),
    },
-   {NULL, NULL, 0, NULL} // sentinel
+   {NULL, NULL, 0, NULL} /* sentinel */
 };
 
 static struct PyModuleDef moduledef = {